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351. Sparsity-based restoration of SMOS images in the presence of outliers

Author: Pablo Musé, Ali Khazaal, B. Rouge, Javier Preciozzi, Andrés Almansa, Sylvain Durand, Yann Kerr, Francois Cabot, Mathématiques Appliquées à Paris 5 ( MAP5 - UMR 8145 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National des Sciences Mathématiques et de leurs Interactions-Centre National de la Recherche Scientifique ( CNRS ), Instituto de Ingeniería Eléctrica (IIE), Universidad de la República [Montevideo] (UCUR), Instituto de Computacion [Montevideo] (INCO), Mathématiques Appliquées Paris 5 (MAP5 - UMR 8145), Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Ingeniería Eléctrica ( IIE ), Universidad de la República, Instituto de Computacion [Montevideo] ( INCO ), Universidad de la República [Montevideo] ( UCUR ), Centre d'études spatiales de la biosphère ( CESBIO ), Université Toulouse III - Paul Sabatier ( UPS ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Durand, Sylvain
Subjects: Brightness, [ INFO.INFO-TS ] Computer Science [cs]/Signal and Image Processing, Computer science, Aperture synthesis, 0211 other engineering and technologies, 02 engineering and technology, [ SPI.SIGNAL ] Engineering Sciences [physics]/Signal and Image processing, Physics::Geophysics, symbols.namesake, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, 0202 electrical engineering, electronic engineering, information engineering, Water content, Image restoration, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, Remote sensing, [SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing, Salinity, Interferometry, 13. Climate action, Gaussian noise, Brightness temperature, Outlier, symbols, 020201 artificial intelligence & image processing, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: Estimates of soil moisture and surface salinity are of significant importance to improve meteorological and climate prediction. The SMOS mission monitor these quantities, by measuring the brightness temperature by means of L-band aperture synthesis interferometry. Despite the L-band being reserved for Earth and space exploration, SMOS images reveal large number of strong outliers, produced by illegal antennas emitting in this band. In this work we propose a variational approach to recover a super-resolved, denoised brightness temperature map. The measurements are modeled as the superposition of three super-resolved components in the spatial domain: the target brightness temperature map u, an image o modeling the outliers, and Gaussian noise n. This decomposition allows to isolate each of its constituent parts, thanks to a sparsity operator that acts on o, and a bounded variation prior on u that extrapolates its spectrum promoting a non-oscillating behavior. The proposed model is interesting in itself, as it is general enough to be applied to other restoration problems. Experiments on real and synthetic data confirm the suitability of the proposed approach.
Published: 2012

352. Testing and improving forward model and SMOS L2 algorithm for forests

Author: P. Richaume, Paolo Ferrazzoli, R. Rahmoune, and Yann Kerr
Subjects: Brightness, Brightness temperature, Environmental science, Vegetation, Atmospheric temperature, Algorithm, Water content, Optical depth, World map, Physics::Geophysics, Remote sensing
Abstract: This paper introduces a revised version of the forward model adopted by the SMOS SM algorithm to represent forest emission. The forward model is tested against multitemporal measurements of brightness temperature obtained over a US forest. World map of retrieved optical depth and soil moisture are also presented.
Published: 2012
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353. The AACES field experiments: SMOS calibration and validation across the Murrumbidgee River catchment

Author: Yann Kerr, Edward J. Kim, Nan Ye, Christoph Rudiger, M. Allahmoradi, Jeffrey P. Walker, Sandy Peischl, and Ranmalee Sajeewanie Bandara
Subjects: Hydrology, lcsh:GE1-350, Soil texture, lcsh:T, lcsh:Geography. Anthropology. Recreation, Vegetation, lcsh:Technology, lcsh:TD1-1066, Ancillary data, lcsh:G, Brightness temperature, Environmental science, Satellite, Leaf area index, lcsh:Environmental technology. Sanitary engineering, Scale (map), Water content, lcsh:Environmental sciences, Remote sensing
Abstract: Following the launch of the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission on 2 November 2009, SMOS soil moisture products need to be rigorously validated at the satellite's approximately 45 km scale and disaggregation techniques for producing maps with finer resolutions tested. The Australian Airborne Cal/val Experiments for SMOS (AACES) provide the basis for one of the most comprehensive assessments of SMOS data world-wide by covering a range of topographic, climatic and land surface variability within an approximately 500 × 100 km2 study area, located in South-East Australia. The AACES calibration and validation activities consisted of two extensive field experiments which were undertaken across the Murrumbidgee River catchment during the Australian summer and winter season of 2010, respectively. The datasets include airborne L-band brightness temperature, thermal infrared and multi-spectral observations at 1 km resolution, as well as extensive ground measurements of near-surface soil moisture and ancillary data, such as soil temperature, soil texture, surface roughness, vegetation water content, dew amount, leaf area index and spectral characteristics of the vegetation. This paper explains the design and data collection strategy of the airborne and ground component of the two AACES campaigns and presents a preliminary analysis of the field measurements including the application and performance of the SMOS core retrieval model on the diverse land surface conditions captured by the experiments. The data described in this paper are publicly available from the website: http://www.moisturemap.monash.edu.au/aaces.
Published: 2012
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354. SMOS vole au-dessus de nos têtes

Author: Jacqueline Boutin, Yann Kerr, Philippe Waldteufel, ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL)
Subjects: Épaisseur optique, Radar, Humidité sol, Transfert radiatif, Interferométrie, Télédétection satellitaire, Couvert végétal, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Satellite artificiel, Observation météorologique, Rayonnement surface terrestre, Simulation numérique, Méthode observation océanographique, Rayonnement thermique, Radiométrie, Salinité eau, 14. Life underwater, Rugosité mer, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, Correction d'erreur, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; Lancée en novembre 2009, la mission SMOS (Soil Moisture and Ocean Salinity) est triplement ambitieuse par ses finalités : elle est destinée à mesurer systématiquement des quantités physiques - humidité du sol et salinité à la surface de la mer - de haute signification dans le système climatique ,son parti pris technique innovant de radiométrie interférométrique, ses choix en matière d'extraction des quantités recherchées, choix qui mettent en oeuvre des modélisations explicites du transfert radiatif. Même si l'évaluation exhaustive des résultats de SMOS devra attendre la fin de la mission et certainement au delà, le temps est venu d'apprécier les chances que les défis posés soient relevés avec succès.
Published: 2012
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355. The soil moisture and ocean salinity (SMOS) mission: first results and achievements

Author: Jean-Pierre Wigneron, Philippe Richaume, Jacqueline Boutin, Susanne Mecklenburg, Arnaud Mialon, Yann Kerr, Ahmad Al Bitar, Philippe Waldteufel, Nicolas Reul, Delphine Leroux, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Vega Technologies, Partenaires INRAE, European Space Research Institute (ESRIN), European Space Agency (ESA), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: QA71-90, salinité des océans, Forestry, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Instruments and machines, radiométrie en bande L, Computer Science Applications, TA1501-1820, Salinity, interférométrie, humidité des sols, HE9713-9715, mission SMOS, Environmental science, Applied optics. Photonics, 14. Life underwater, Electrical and Electronic Engineering, Cellular telephone services industry. Wireless telephone industry, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: National audience; La mission SMOS (Soil moisture and Ocean Salinity) a été lancée avec succès le 2 novembre 2009. Cette mission menée par l'ESA (Agence Spatiale Europénne) est dédiée à la mesure de l'humidité superficielle des sols sur les continents (avec une précision recherchée de 0,04m3/m3) et la salinité des océans (objectif 0.1psu). Ces deux quantités géophysiques sont très importantes car elle contrôle le budget énergétique à l'interface sol-atmosphère. Leur connaissance à l'échelle globale est utile pour les recherches sur le climat et la météorologie, en particulier pour les modèles de prévision numérique. Elles ont aussi un très grand potentiel un très grand nombre d'application, comme par exemple pour le suivi des ouragans ou la gestion des ressources en eau. Les six premiers mois ont été dédiés à la recette en vol qui a permis de vérifier le satellite le segment sol et l'étalonnage. Cette phase s'est achevée avec succès en mai 2010 et SMOS fonctionne de façon opérationnelle depuis, fournissant de données à la communauté internationale. Les performances de l'instrument sont globalement conformes aux spécifications. Cependant, les interférences radio sont présentes au-dessus de l'Europe, du Moyen-Orient et de l'Asie. Cesémissions parasites dans la bande protégée perturbent la mesure de façon significative. La génération des produits de niveau 2 et 3 est une activité en cours avec des améliorations régulières de sorties.
Published: 2012
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356. ESA's Soil Moisture and Ocean Salinity Mission: Mission Performance and Operations

Author: Yann Kerr, Nicolas Reul, Guillermo Buenadicha, Manuel Martin-Neira, Jordi Font, Susanne Mecklenburg, Roger Oliva, E. Daganzo-Eusebio, R. Crapolicchio, Matthias Drusch, Steven Delwart, European Space Research Institute (ESRIN), European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Astronomy Centre (ESAC), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Agence Spatiale Européenne = European Space Agency (ESA), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Soil Moisture and Ocean Salinity Mission, 010504 meteorology & atmospheric sciences, Meteorology, satellite remote sensing, 0211 other engineering and technologies, Soil Moisture and Ocean Salinity, 02 engineering and technology, 7. Clean energy, 01 natural sciences, Data acquisition, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Satellite remote sensing, L-band radiometry, Ground segment, Electrical and Electronic Engineering, sea surface salinity, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Spacecraft, business.industry, [SDE.IE]Environmental Sciences/Environmental Engineering, Flagging, Soil Moisture and Ocean Salinity (SMOS) mission, SSS, Salinity, Sea surface salinity, 13. Climate action, Data quality, General Earth and Planetary Sciences, Environmental science, Radiometry, Soil moisture, soil moisture, business, SMOS
Abstract: Mecklenburg, S. ... et. al., The European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission was launched on the 2nd of November 2009. The first six months after launch, the so-called commissioning phase, were dedicated to test the functionalities of the spacecraft, the instrument, and the ground segment including the data processors. This phase was successfully completed in May 2010, and SMOS has since been in the routine operations phase and providing data products to the science community for over a year. The performance of the instrument has been within specifications. A parallel processing chain has been providing brightness temperatures in near-real time to operational centers, e.g., the European Centre for Medium-Range Weather Forecasts. Data quality has been within specifications; however, radio-frequency interference (RFI) has been detected over large parts of Europe, China, Southern Asia, and the Middle East. Detecting and flagging contaminated observations remains a challenge as well as contacting national authorities to localize and eliminate RFI sources emitting in the protected band. The generation of Level 2 soil moisture and ocean salinity data is an ongoing activity with continuously improved processors. This article will summarize the mission status after one year of operations and present selected first results. © 2012 IEEE
Published: 2012
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357. Validation of soil moisture and ocean salinity (SMOS). Soil moisture over watershed networks in the U.S

Author: Yann Kerr, David C. Goodrich, Tianjie Zhao, Delphine Leroux, Michael H. Cosh, Mark S. Seyfried, David D. Bosch, Rajat Bindlish, M.S. Moran, Patrick J. Starks, Thomas J. Jackson, USDA Agricultural Research Service [Maricopa, AZ] (USDA), United States Department of Agriculture (USDA), United States Department of Agriculture, United States Department of Agriculture (USDA)-United States Department of Agriculture (USDA), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Watershed, 010504 meteorology & atmospheric sciences, Meteorology, 0207 environmental engineering, 02 engineering and technology, 01 natural sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Electrical and Electronic Engineering, 020701 environmental engineering, Water content, 0105 earth and related environmental sciences, Remote sensing, validation, Radiometer, Moisture, Advanced Microwave Scanning Radiometer (AMSR-E), Vegetation, Replicate, 6. Clean water, Soil Moisture and Ocean Salinity (SMOS), 13. Climate action, General Earth and Planetary Sciences, Radiometry, Environmental science, Satellite, soil moisture, passive microwave
Abstract: International audience; Estimation of soil moisture at large scale has been performed using several satellite-based passive microwave sensors and a variety of retrieval methods over the past two decades. The most recent source of soil moisture is the European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission. A thorough validation must be conducted to insure product quality that will, in turn, support the widespread utilization of the data. This is especially important since SMOS utilizes a new sensor technology and is the first passive L-band system in routine operation. In this paper, we contribute to the validation of SMOS using a set of four in situ soil moisture networks located in the U.S. These ground-based observations are combined with retrievals based on another satellite sensor, the Advanced Microwave Scanning Radiometer (AMSR-E). The watershed sites are highly reliable and address scaling with replicate sampling. Results of the validation analysis indicate that the SMOS soil moisture estimates are approaching the level of performance anticipated, based on comparisons with the in situ data and AMSR-E retrievals. The overall root-mean-square error of the SMOS soil moisture estimates is 0.043 m3/m3 for the watershed networks (ascending). There are bias issues at some sites that need to be addressed, as well as some outlier responses. Additional statistical metrics were also considered. Analyses indicated that active or recent rainfall can contribute to interpretation problems when assessing algorithm performance, which is related to the contributing depth of the satellite sensor. Using a precipitation flag can improve the performance. An investigation of the vegetation optical depth (tau) retrievals provided by the SMOS algorithm indicated that, for the watershed sites, these are not a reliable source of information about the vegetation canopy. The SMOS algorithms will continue to be refined as feedback from validation is evaluated, and it is expected that the SMOS estimates will improve.
Published: 2012
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358. Wheat canopy structure and surface roughness effects on multiangle observations at L-Band

Author: Rocco Panciera, Yann Kerr, Jeffrey P. Walker, Christoph Rudiger, Dongryeol Ryu, Sandy Peischl, Department of Civil and Environmental Engineering [Melbourne], University of Melbourne, Department of Infrastructure Engineering [Melbourne], Melbourne School of Engineering [Melbourne], University of Melbourne-University of Melbourne, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Cooperative Research Centre for Spatial Information (CRCSI), Government of Western Australia, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Field experiment, 0211 other engineering and technologies, Soil science, 02 engineering and technology, Surface finish, 01 natural sciences, National Airborne Field Experiment (NAFE), [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, multiangle, Surface roughness, 14. Life underwater, Electrical and Electronic Engineering, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Moisture, Soil physics, Soil Moisture and Ocean Salinity (SMOS), 15. Life on land, Brightness temperature, General Earth and Planetary Sciences, Environmental science, microwave radiometry, L-band Microwave Emission of the Biosphere (L-MEB)
Abstract: International audience; The multiangle observation capability of the Soil Moisture and Ocean Salinity mission is expected to significantly improve the inversion of soil microwave emissions for soil moisture, by enabling the simultaneous retrieval of the vegetation optical depth and other surface parameters. Consequently, this paper investigates the relationship between soil moisture and brightness temperature at multiple incidence angles using airborne L-band data from the National Airborne Field Experiment in Australia in 2005. A forward radio brightness model was used to predict the passive microwave response at a range of incidence angles, given the following inputs: 1) ground-measured soil and vegetation properties and 2) default model parameters for vegetation and roughness characterization. Simulations weremade across various dates and locations with wheat cover and evaluated against the available airborne observations. The comparison showed a significant underestimation of the measured brightness temperatures by the model. This discrepancy subsequently led to soil moisture retrieval errors of up to 0.3 m3/m3. Further analysis found the following: 1) The roughness value HR was too low, which was then adjusted as a function of the soil moisture, and 2) the vegetation structure parameters tth and ttv required optimization, yielding new values of tth = 0.2 and ttv = 1.4 from calibration to a single flight. Testing the optimized parameterization for different moisture conditions and locations found that the rootmean- square simulation error between the forward model predictions and the airborne observations was improved from 31.3 K (26.5 K) to 2.3 K (5.3 K) for wet (dry) soil moisture condition.
Published: 2012
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359. Spatial and temporal variability of biophysical variables in southwestern France from airborne L-band radiometry

Author: Jean-Pierre Wigneron, Jean-Christophe Calvet, Yann Kerr, Sébastien Lafont, Mehrez Zribi, Mickaël Pardé, Clément Albergel, Elena Zakharova, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), European Centre for Medium-Range Weather Forecasts (ECMWF), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), STAE (Sciences et Technologies pour l'Aeronautique et l'Espace) foundation, Centre National d'Etudes Spatiales (CNES), Meteo-France, 'Programme Terre Ocean Surface Continentales et Atmosphere' (TOSCA, CNES), GEOLAND2 project, European Commission within the GMES initiative in FP7, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: analyse de données, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, 0207 environmental engineering, teneur en eau, 02 engineering and technology, température de brillance, radiomètre, surface foliaire, Atmospheric sciences, Spatial distribution, lcsh:Technology, 01 natural sciences, lcsh:TD1-1066, 14. Life underwater, lcsh:Environmental technology. Sanitary engineering, Leaf area index, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, Milieux et Changements globaux, 020701 environmental engineering, Water content, lcsh:Environmental sciences, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, lcsh:GE1-350, Radiometer, lcsh:T, lcsh:Geography. Anthropology. Recreation, Biosphere, Vegetation, 15. Life on land, télédétection, mission SMOS, microonde passive, modèle L-MEB, lcsh:G, Brightness temperature, Environmental science, Spatial variability, sud ouest france
Abstract: In 2009 and 2010 the L-band microwave Cooperative Airborne Radiometer for Ocean and Land Studies (CAROLS) campaign was performed in southwestern France to support the calibration and validation of the new Soil Moisture and Ocean Salinity (SMOS) satellite mission. The L-band Microwave Emission of the Biosphere (L-MEB) model was used to retrieve surface soil moisture (SSM) and the vegetation optical depth (VOD) from the CAROLS brightness temperature measurements. The CAROLS SSM was compared with in situ observations at 11 sites of the SMOSMANIA (Soil Moisture Observing System-Meteorological Automatic Network Integrated Application) network of Météo-France. For eight of them, significant correlations were observed (0.51 ≤ r ≤ 0.82), with standard deviation of differences ranging from 0.039 m3 m−3 to 0.141 m3 m−3. Also, the CAROLS SSM was compared with SSM values simulated by the A-gs version of the Interactions between Soil, Biosphere and Atmosphere (ISBA-A-gs) model along 20 flight lines, at a resolution of 8 km × 8 km. A significant spatial correlation between these two datasets was observed for all the flights (0.36 ≤ r ≤ 0.85). The CAROLS VOD presented significant spatial correlations with the vegetation water content (VWC) derived from the spatial distribution of vegetation types used in ISBA-A-gs and from the Leaf Area Index (LAI) simulated for low vegetation. On the other hand, the CAROLS VOD presented little temporal changes, and no temporal correlation was observed with the simulated LAI. For low vegetation, the ratio of VOD to VWC tended to decrease, from springtime to summertime. The ISBA-A-gs grid cells (8 km × 8 km) were sampled every 5 m by CAROLS observations, at a spatial resolution of about 2 km. For 83% of the grid cells, the standard deviation of the sub-grid CAROLS SSM was lower than 0.05 m3 m−3. The presence of small water bodies within the ISBA-A-gs grid cells tended to increase the CAROLS SSM spatial variability, up to 0.10 m3 m−3. Also, the grid cells characterised by a high vegetation cover heterogeneity presented higher standard deviation values, for both SSM and VOD.
Published: 2012
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360. The SMOS Soil Moisture Retrieval Algorithm

Author: Paolo Ferrazzoli, Arnaud Mialon, Yann Kerr, P. Richaume, Ahmad Al Bitar, Philippe Waldteufel, A. Mahmoodi, C. Gruhier, Delphine Leroux, Francois Cabot, S. Juglea, Steven Delwart, Jean-Pierre Wigneron, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Università degli Studi di Roma Tor Vergata [Roma], Array Systems, University of Toronto, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Agence Spatiale Européenne = European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Meteorology, [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, Context (language use), 02 engineering and technology, 01 natural sciences, vegetation opacity, Cal/Val, Surface roughness, Emissivity, Ground segment, Electrical and Electronic Engineering, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, model, Payload, Ocean chemistry, Settore ING-INF/02 - Campi Elettromagnetici, Orbit (dynamics), General Earth and Planetary Sciences, Environmental science, Radiometry, retrievals, soil moisture, SMOS
Abstract: International audience; The Soil Moisture and Ocean Salinity (SMOS) mission is European Space Agency (ESA's) second Earth Explorer Opportunity mission, launched in November 2009. It is a joint program between ESA Centre National d'Etudes Spatiales (CNES) and Centro para el Desarrollo Tecnologico Industrial. SMOS carries a single payload, an L-Band 2-D interferometric radiometer in the 1400-1427 MHz protected band. This wavelength penetrates well through the atmosphere, and hence the instrument probes the earth surface emissivity. Surface emissivity can then be related to the moisture content in the first few centimeters of soil, and, after some surface roughness and temperature corrections, to the sea surface salinity over ocean. The goal of the level 2 algorithm is thus to deliver global soil moisture (SM) maps with a desired accuracy of 0.04 m3/m3. To reach this goal, a retrieval algorithm was developed and implemented in the ground segment which processes level 1 to level 2 data. Level 1 consists mainly of angular brightness temperatures (TB), while level 2 consists of geophysical products in swath mode, i.e., as acquired by the sensor during a half orbit from pole to pole. In this context, a group of institutes prepared the SMOS algorithm theoretical basis documents to be used to produce the operational algorithm. The principle of the SM retrieval algorithm is based on an iterative approach which aims at minimizing a cost function. The main component of the cost function is given by the sum of the squared weighted differences between measured and modeled TB data, for a variety of incidence angles. The algorithm finds the best set of the parameters, e.g., SM and vegetation characteristics, which drive the direct TB model and minimizes the cost function. The end user Level 2 SM product contains SM, vegetation opacity, and estimated dielectric constant of any surface, TB computed at 42.5$^{circ}$, flags and quality indices, and other parameters o- interest. This paper gives an overview of the algorithm, discusses the caveats, and provides a glimpse of the Cal Val exercises.
Published: 2012
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361. L-Band radiative properties of vine vegetation at the MELBEX III SMOS Cal/Val Site

Author: Yann Kerr, Christian Mätzler, Mike Schwank, Ingo Völksch, Ernesto Lopez-Baeza, Jean-Pierre Wigneron, German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Universitat de València (UV), Institut Fédéral de Recherches sur la Forêt, la Neige et le Paysage (WSL), Institut Fédéral de Recherches [Suisse], Institute of Applied Physics [Bern] (IAP), University of Bern, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Valence, University of Valencia, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Geoecology and Geomorphology, geoecology, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and CGR Centre for Geoecological Research, Geoengineering Centres, GFZ Publication Database, Deutsches GeoForschungsZentrum
Subjects: Mediterranean climate, Brightness, 010504 meteorology & atmospheric sciences, vegetation mapping, 0211 other engineering and technologies, Microwave radiometry, 550 - Earth sciences, 02 engineering and technology, Atmospheric sciences, 01 natural sciences, Vineyard, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Radiative transfer, Electrical and Electronic Engineering, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, Vegetation, 15. Life on land, radiative transfer, Brightness temperature, Soil water, General Earth and Planetary Sciences, Environmental science, soil moisture
Abstract: Radiative properties at 1.4 GHz of vine vegetation are investigated by measuring brightness temperatures with the ETH L-band Radiometer II (ELBARA II) operated on a tower at the Mediterranean Ecosystem L-band Characterisation Experiment III (MELBEX III) field site in Spain. To this aim, experiments with and without a reflecting foil placed under the vines were performed for the vegetation winter and summer states, respectively, to provide prevailingly information on vegetation transmissivities. The resulting parameters, which can be considered as "ground truth" for the MELBEX III vineyard, were retrieved from brightness temperature at horizontal and vertical polarization measured at observation angles between 30◦ and 60◦. These MELBEX III "ground-truth" values are representative for the Mediterranean Soil Moisture and Ocean Salinity (SMOS) Valencia Anchor Station (VAS) and therefore valuable for the corresponding calibration and validation activities over the VAS site. Likewise, quantifying the uncertainties of the measured brightness temperatures was also important, particularly as several equivalent ELBARA II instruments are currently operative in ongoing SMOS-related field campaigns.
Published: 2012
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362. Toward the development of a multidirectional vegetation index

Author: Yann Kerr, Alfredo Huete, Soroosh Sorooshian, Jiaguo Qi, and A. Chehbouni
Subjects: Canopy, Watershed, Gulch, Shadow, Nadir, medicine, Environmental science, Enhanced vegetation index, medicine.symptom, Vegetation (pathology), Anisotropy, Water Science and Technology, Remote sensing
Abstract: Vegetation-related information is critical for modeling hydrological processes. Remotely sensed spectral data provide powerful means to characterize vegetation status. However, the non-Lambertian behavior of most surfaces induces a large view/Sun angle dependence. Two approaches are possible to correct such contamination. One approach consists of using directional reflectance models; the other consists of normalizing the Sun/view angle effects directly on vegetation indices that have the advantage of being less sensitive to surface anisotropy than individual reflectances. Ground-based multiple view direction/angle measurements made over a semiarid grassland canopy at the Walnut Gulch experiment watershed (Monsoon '90 experiment) were used to develop and to validate a semiempirical model to normalize the MSAVI (modified soil-adjusted vegetation index) response to a nadir, regardless of view/direction angle. We further advanced this model to account simultaneously for both Sun and view angle variations by introducing a shadow parameterization. The results showed that this model can be used to monitor the vegetation status using a single view/Sun configuration throughout the growing season. We therefore believe that we have taken a further step toward the development of a multidirectional vegetation index.
Published: 1994
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363. A modified soil adjusted vegetation index

Author: Soroosh Sorooshian, Alfredo Huete, A. Chehbouni, Yann Kerr, and Jiaguo Qi
Subjects: Canopy, Hydrology, Soil Science, Geology, Soil science, Global change, Enhanced vegetation index, Geological & Geomatics Engineering, Normalized Difference Vegetation Index, Atmosphere, medicine, Environmental science, Computers in Earth Sciences, Vegetation Index, medicine.symptom, Vegetation (pathology), Remote sensing
Abstract: There is currently a great deal of interest in the quantitative characterization of temporal and spatial vegetation patterns with remotely sensed data for the study of earth system science and global change. Spectral models and indices are being developed to improve vegetation sensitivity by accounting for atmosphere and soil effects. The soil-adjusted vegetation index (SAVI) was developed to minimize soil influences on canopy spectra by incorporating a soil adjustment factor L into the denominator of the normalized difference vegetation index (NDVI) equation. For optimal adjustment of the soil effect, however, the L factor should vary inversely with the amount of vegetation present. A modified SAVI (MSAVI) that replaces the constant L in the SAVI equation with a variable L function is presented in this article. The L function may be derived by induction or by using the product of the NDVI and weighted difference vegetation index (WDVI). Results based on ground and aircraft-measured cotton canopies are presented. The MSAVI is shown to increase the dynamic range of the vegetation signal while further minimizing the soil background influences, resulting in greater vegetation sensitivity as defined by a "vegetation signal" to "soil noise" ratio. © 1994.
Published: 1994
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364. Plant water content and temperature of the Amazon forest from satellite microwave radiometry

Author: Jean-Christophe Calvet, Jean-Pierre Wigneron, Yann Kerr, Eric Mougin, and J.L.S. Brito
Subjects: 010504 meteorology & atmospheric sciences, Microwave radiometer, Scanning multichannel microwave radiometer, 0211 other engineering and technologies, Atmospheric correction, 02 engineering and technology, 15. Life on land, Atmospheric temperature, 01 natural sciences, Microwave imaging, General Earth and Planetary Sciences, Environmental science, Radiometry, Electrical and Electronic Engineering, Water vapor, Microwave, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing
Abstract: An attempt is made to derive the evolution of the temperature and the water status of the Amazon forest canopy from satellite microwave radiometry. The Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) temperature-corrected tapes data are analyzed for the 6.6, 10.7, 18, and 37 GHz frequencies, at daytime and nighttime, over a zone near Manaus (3/spl deg/S, 60/spl deg/W), Brazil. Two periods are investigated: the wet (April-May) and dry (July-August) seasons of 1985. After separating forest- from river-contaminated pixels, atmospheric corrections are performed for water vapor, clouds, and rain, using surface and satellite data. Algorithms are developed to model the microwave thermal emission of vegetation following a continuous approach and a discrete approach. A sensitivity study is performed in order to determine which frequencies are relevant to retrieve land surface parameters. The models are then used along with an optimization procedure so as to carry out the inversion of the canopy structure parameters. The vegetation temperature and water content are retrieved through the continuous model. >
Published: 1994
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365. Evaluating an Improved Parameterization of the Soil Emission in L-MEB

Author: Jiancheng Shi, Arnaud Mialon, Jean-Pierre Wigneron, Valery Mironov, Yann Kerr, M. J. Escorihuela, K. Saleh-Contell, Andre Chanzy, P. de Rosnay, Heather Lawrence, François Demontoux, Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Institute for Computational Earth System Science [Santa Barbara] (ICESS), University of California [Santa Barbara] (UCSB), University of California-University of California, Radiophysics of remote sensing laboratory, Kirensky Institute of Physics, European Centre for Medium-Range Weather Forecasts (ECMWF), CNES, SMOS, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], 0211 other engineering and technologies, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Soil science, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, Surface finish, radiometry, 01 natural sciences, Standard deviation, Soil, Surface roughness, Geophysical measurements, Calibration, Electrical and Electronic Engineering, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Mathematics, roughness, soil surface, Temperature measurement, Moisture, soil moisture (SM), Rough surfaces, L-band, Microwave remote sensing, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Soil Moisture and Ocean Salinity (SMOS), Soil measurements, Soil water, General Earth and Planetary Sciences, Radiometry
Abstract: Correction to "Evaluating an improved parameterization of the soil emission in L-MEB" dans Geoscience and Remote Sensing, IEEE Transactions on (Volume: 51, Issue: 5 ) In the above paper (ibid., vol. 49, no. 4, pp. 1177-1189, Apr. 2011), there is an error in equation (7). The explanation and corrected equation are presented here. http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6495716; International audience; In the forward model [L-band microwave emission of the biosphere (L-MEB)] used in the Soil Moisture and Ocean Salinity level-2 retrieval algorithm, modeling of the roughness effects is based on a simple semiempirical approach using three main “roughness” model parameters: HR, QR, and NR. In many studies, the two parameters QR and NR are set to zero. However, recent results in the literature showed that this is too approximate to accurately simulate the microwave emission of the rough soil surfaces at L-band. To investigate this, a reanalysis of the PORTOS-93 data set was carried out in this paper, considering a large range of roughness conditions. First, the results confirmed that QR could be set to zero. Second, a refinement of the L-MEB soil model, considering values of NR for both polarizations (namely, NRV and NRH), improved the model accuracy. Furthermore, simple calibrations relating the retrieved values of the roughness model parameters HR and (NRH − NRV) to the standard deviation of the surface height were developed. This new calibration of L-MEB provided a good accuracy (better than 5 K) over a large range of soil roughness and moisture conditions of the PORTOS-93 data set. Conversely, the calibrations of the roughness effects based on the Choudhury approach, which is still widely used, provided unrealistic values of surface emissivities for medium or large roughness conditions.
Published: 2011
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366. First evaluation of the SMOS observations over the VAS site

Author: Jean-Pierre Wigneron, Mike Schwank, Ernesto Lopez-Baeza, Yann Kerr, Nathalie Novello, Christophe Moisy, Dominique Guyon, Heather Lawrence, Ahmad Al Bitar, François Cabot, Claire Gruhier, Silvia Juglea, Delphine Leroux, Arnaud Mialon, Philippe Richaume, Jennifer Grant, Philippe Waldteufel, Ali Mahmoodi, Steven Delwart, Susanne Mecklenburg, Cristina Millan, Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Universitat de València (UV), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Agence Spatiale Européenne = European Space Agency (ESA), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Array Systems Computing, Partenaires INRAE, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and European Space Agency (ESA)
Subjects: SMOS (Soil Moisture and Ocean Salinity) MISSION, RADIOMETER, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences
Abstract: International audience; The SMOS (Soil Moisture and Ocean Salinity) mission was launched on November 2, 2009. Over the land surfaces, simultaneous retrievals of surface soil moisture (SM) and vegetation characteristics are made from the multi-angular and dual polarization SMOS observations by inverting the L-MEB (L-band Microwave Emission of the Biosphere) model. Preliminary analyses evaluating the SMOS observations in terms of Brightness Temperatures (TB) and Level-2 products (SM and vegetation optical depth TAU) were carried out over several sites of all continents. Here, the study is based on SMOS observations and in situ measurements carried out in 2010 over one of the main SMOS calibration/validation sites in Europe: the VAS (Valencia Anchor Station) site in the region of Utiel–Requena, close to Valencia, Spain. The main vegetation types in the region are vineyards (cover fraction ~60%), natural Mediterranean vegetation (pine trees and shrubs ~30%) and orchards. The SMOS observations were analysed in conjunction with those carried out by the L-band ELBARA II radiometer over a vineyard which is representative of the main land use of the VAS site. Retrievals of SM and TAU based on the SMOS observations (Level-2 products) and the ELBARA II instrument were compared and evaluated against in situ measurements and simulations of SM by atmospheric models. A good agreement was found between the time variations in SM over the site retrieved from the SMOS and ELBARA II observations. However, it was found the SMOS Level-2 products underestimated SM by about 0.15 %, even though it is difficult to estimate SM values at large scale that can be considered as a "reference" to evaluate the SMOS SM retrievals. Retrievals computed from SMOS data using a simplified L-MEB version, that did not consider the pixel heterogeneity and the WEF function, produced very satisfying results (R2=66% when compared to retrievals computed from the ELBARA II observations) The time variations in the retrieved TAU computed from the ELBARA II observations could be closely related to those of the NDVI vegetation index, obtained from the MODIS observations in the optical domain. Conversely, the time variations in the SMOS Level-2 TAU product seemed to be strongly affected by microwave interferences over the site.
Published: 2011

367. Comparing soil moisture retrievals from SMOS and ASCAT over France

Author: Yann Kerr, Sébastien Lafont, Wolfgang Wagner, Elena Zakharova, Jean-Pierre Wigneron, Jean-Christophe Calvet, Marie Parrens, Météo France, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Vienna University of Technology, Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Météo-France Direction Interrégionale Sud-Est (DIRSE), Météo-France, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: analyse de données, 010504 meteorology & atmospheric sciences, télédétection, [SDV]Life Sciences [q-bio], satellite, 0207 environmental engineering, 0211 other engineering and technologies, modèle isba, airborne campaign, 02 engineering and technology, Atmospheric sciences, lcsh:Technology, 01 natural sciences, lcsh:TD1-1066, in-situ observations land-surface parameterization, L-band, ERS scatterometer, microwave radiometer, data assimilation, mission SMOS, humidité du sol, lcsh:Environmental technology. Sanitary engineering, Leaf area index, 020701 environmental engineering, Water content, lcsh:Environmental sciences, ComputingMilieux_MISCELLANEOUS, Remote sensing, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, lcsh:GE1-350, lcsh:T, Anomaly (natural sciences), lcsh:Geography. Anthropology. Recreation, Scatterometer, On board, lcsh:G, 13. Climate action, [SDE]Environmental Sciences, Environmental science, Satellite
Abstract: The first products derived over France in 2010 from the L-band brightness temperatures (Tb) measured by the SMOS (Soil Moisture and Ocean Salinity) satellite, launched in November 2009, were compared with the surface soil moisture (SSM) estimates produced by the C-band Advanced Scatterometer, ASCAT, launched in 2006 on board METOP-A. SMOS and ASCAT SSM products were compared with the simulations of the ISBA-A-gs model and with in situ measurements from the SMOSMANIA network, including 21 stations located in southern France. ASCAT tended to correlate better than SMOS with ISBA-A-gs. The significant anomaly correlation coefficients between in situ observations and the SMOS (ASCAT) product ranged from 0.23 to 0.48 (0.35 to 0.96). However, in wet conditions, similar results between the two satellite products were found. An attempt was made to derive SSM from regressed empirical logarithmic equations using a combination of SMOS Tb at different incidence angles and different polarizations, and the Leaf Area Index (LAI) modeled by ISBA-A-gs. The analysis of the intercept coefficient of the regression showed an impact of topography. A similar analysis applied to ASCAT and SMOS SSM values showed a more limited impact of topography on the intercept coefficient of the SMOS SSM product, while fewer residual geographic patterns were found for the ASCAT SSM.
Published: 2011
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368. Downscaling SMOS-derived soil moisture using MODIS visible/infrared data

Author: Adriano Camps, Yann Kerr, Jeffrey P. Walker, Maria Piles, Rocco Panciera, Mercè Vall-llossera, Christoph Rudiger, Ignasi Corbella, Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. RSLAB - Grup de Recerca en Teledetecció, and Universitat Politècnica de Catalunya. RF&MW - Grup de Recerca de sistemes, dispositius i materials de RF i microones
Subjects: Vegetation mapping, Radiometer, Sistemes d'informació geogràfica, 010504 meteorology & atmospheric sciences, 0207 environmental engineering, Microwave measurements, 02 engineering and technology, 15. Life on land, 01 natural sciences, Normalized Difference Vegetation Index, Visible infrared, Microones -- Mesurament, High spatial resolution, General Earth and Planetary Sciences, Radiometry, Environmental science, 14. Life underwater, Enginyeria de la telecomunicació::Radiocomunicació i exploració electromagnètica::Satèl·lits i ràdioenllaços [Àrees temàtiques de la UPC], Electrical and Electronic Engineering, 020701 environmental engineering, Water content, Image resolution, 0105 earth and related environmental sciences, Remote sensing, Downscaling
Abstract: A downscaling approach to improve the spatial resolution of Soil Moisture and Ocean Salinity (SMOS) soil moisture estimates with the use of higher resolution visible/infrared (VIS/IR) satellite data is presented. The algorithm is based on the so-called “universal triangle” concept that relates VIS/IR parameters, such as the Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (Ts), to the soil moisture status. It combines the accuracy of SMOS observations with the high spatial resolution of VIS/IR satellite data into accurate soil moisture estimates at high spatial resolution. In preparation for the SMOS launch, the algorithm was tested using observations of the UPC Airborne RadIomEter at L-band (ARIEL) over the Soil Moisture Measurement Network of the University of Salamanca (REMEDHUS) in Zamora (Spain), and LANDSAT imagery. Results showed fairly good agreement with ground-based soil moisture measurements and illustrated the strength of the link between VIS/IR satellite data and soil moisture status. Following the SMOS launch, a downscaling strategy for the estimation of soil moisture at high resolution from SMOS using MODIS VIS/IR data has been developed. The method has been applied to some of the first SMOS images acquired during the commissioning phase and is validated against in situ soil moisture data from the OZnet soil moisture monitoring network, in South-Eastern Australia. Results show that the soil moisture variability is effectively captured at 10 and 1 km spatial scales without a significant degradation of the root mean square error.
Published: 2011

369. Evaluation of SMAP level 2 soil moisture algorithms using SMOS data

Author: Thomas J. Jackson, Jiancheng Shi, S. Chan, Andreas Colliander, Tianjie Zhao, Eni G. Njoku, Rajat Bindlish, Michael H. Cosh, Yann Kerr, and Peggy O'Neill
Subjects: Satellite observation, Radiometer, Moisture measurement, Environmental science, Radiometry, Vegetation, Microwave radiometry, Water content, Algorithm, Retrieval algorithm, Remote sensing
Abstract: SMOS observations provide an opportunity to develop a testbed for the evaluation of different SMAP algorithm options. The use of real-world global observations will help in the development and selection of different land surface parameters and ancillary observations needed for the soil moisture algorithms. In this study, SMOS observations were used with one soil moisture retrieval algorithm and the results were evaluated using in situ soil moisture measurements. The SMOS soil moisture product, which exploits multiple incidence angle observations, compares well with the ground-based observations (RMSE 0.043 m3/m3 (ascending) and 0.047 m3/m3 (descending)). The alternative SMAP compatible algorithm also performed well (RMSE 0.040 m3/m3 (ascending) and 0.043 m3/m3 (descending)). Although preliminary, these initial results are encouraging for the potential of SMAP to meet its required soil moisture accuracy.
Published: 2011
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370. A synergy between SMOS & AQUARIUS: Resampling SMOS maps at the resolution and incidence of AQUARIUS

Author: David M. Le Vine, Gary Lagerloef, Yann Kerr, Eric Anterrieu, and Francois Cabot
Subjects: Radiometer, Microwave Imaging Radiometer with Aperture Synthesis, Microwave imaging, Meteorology, Payload, Observatory, law, Brightness temperature, Environmental science, Radiometry, Radar, Remote sensing, law.invention
Abstract: On one hand, the SMOS mission is an ESA project aimed at global monitoring of surface Soil Moisture and Ocean Salinity from radiometric L-band observations. The single payload of the mission is MIRAS, a Microwave Imaging Radiometer with Aperture Synthesis. It has been successfully lofted into orbit on November 2nd, 2009. On the other hand, AQUARIUS/SAC-D mission is a partnership between NASA and CONAE for monitoring sea surface salinity from space. The observatory includes AQUARIUS, an L-band radiometer/radar combination and the mission is scheduled for launch on June 9th, 2011. This work is concerned with the synergy between both instruments. It is shown how the brightness temperature maps retrieved from MIRAS interferometric measurements can be resampled down to the ground resolution achieved by the three beams of AQUARIUS without introducing any artifact.
Published: 2011
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371. Estimating SMOS error structure using triple collocation

Author: Delphine Leroux, B. Berthelot, P. Richaume, and Yann Kerr
Subjects: Data set, Structure (mathematical logic), Identification (information), Series (mathematics), Calibration, Triple collocation, Water content, Field (computer science), Mathematics, Remote sensing
Abstract: Soil moisture is one of the most important variables regarding climate evolution. It is an ECV (Essential Climate Variable) and there are several data sets of soil moisture derived from satellite data or models. Now time series of soil moisture are available for more than 30 years and it has become important to estimate the error associated to each existing data set. A way to estimate these errors is the triple collocation method. It has already been used to calibrate data sets (in situ measurements, satellite data and model outputs) and to model the errors in the ocean field ([1]). The results of these studies can be the identification of a bias in a data set, of a more accurate data set or of a correlation between the two data sets.
Published: 2011
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372. Soil Moisture Estimations Based on Airborne CAROLS L-Band Microwave Data

Author: Nathalie Novello, Clément Albergel, Mehrez Zribi, Mickaël Pardé, Jean-Pierre Wigneron, K. Saleh, Monique Dechambre, Jean-Christophe Calvet, Marc Crapeau, Yann Kerr, Arnaud Mialon, Pascal Fanise, ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), This work was carried out in the context of a SMOS/ESA Cal/Val project, and was funded by the TOSCA/CNES program. The authors would like to thank the French CNES for the support it gave to the CAROLS project, as well as to all of the CAROLS campaigns. The authors would also like to thank the technical teams from CESBIO, CNRM, LATMOS, LOCEAN, SAFIRE, DT-INSU, DTU, INRA, and the SAFIRE pilots for their support and contributions to the successful airborne and ground campaigns. The MODIS data we used (LAI and NDVI) was made available by the Land Processes Distributed Active Archive Centre (LP DAAC), located at the US Geological Survey (USGS) Earth Resources Observation and Science (EROS) Centre (lpdaac.usgs.gov)., Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: L band, 010504 meteorology & atmospheric sciences, télédétection, satellite, 0211 other engineering and technologies, 02 engineering and technology, radiomètre, 01 natural sciences, CAROLS, Soil roughness, Normalized Difference Vegetation Index, humidité du sol, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, lcsh:Science, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, MISSION SMOS, MODELE L-MEB, Biosphere, Vegetation, 15. Life on land, L-band, L-MEB, General Earth and Planetary Sciences, Environmental science, lcsh:Q, Satellite, Soil moisture, Microwave
Abstract: International audience; The SMOS satellite mission, launched in 2009, allows global soil moisture estimations to be made using the L-band Microwave Emission of the Biosphere (L-MEB) model, which simulates the L-band microwave emissions produced by the soil-vegetation layer. This model was calibrated using various sources of in situ and airborne data. In the present study, we propose to evaluate the L-MEB model on the basis of a large set of airborne data, recorded by the CAROLS radiometer during the course of 20 flights made over South West France (the SMOSMANIA site), and supported by simultaneous soil moisture measurements, made in 2009 and 2010. In terms of volumetric soil moisture, the retrieval accuracy achieved with the L-MEB model, with two default roughness parameters, ranges between 8% and 13%. Local calibrations of the roughness parameter, using data from the 2009 flights for different areas of the site, allowed an accuracy of approximately 5.3% to be achieved with the 2010 CAROLS data. Simultaneously we estimated the vegetation optical thickness (t) and we showed that, when roughness is locally adjusted, MODIS NDVI values are correlated (R2 = 0.36) to t. Finally, as a consequence of the significant influence of the roughness parameter on the estimated absolute values of soil moisture, we propose to evaluate the relative variability of the soil moisture, using a default soil roughness parameter. The soil moisture variations are estimated with an uncertainty of approximately 6%.
Published: 2011
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373. A first assessment of the SMOS data in southwestern France using in situ and airborne soil moisture estimates : the CAROLS airborne campaign

Author: Yann Kerr, Jean-Pierre Wigneron, Nour-Ed-Dine Fritz, Mickaël Pardé, Arnaud Mialon, Clément Albergel, Mehrez Zribi, Nathalie Novello, Jean-Christophe Calvet, Elena Zakharova, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), ' Programme Terre Océan Surface Continentales et Atmosphère ' (TOSCA, CNES), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263)
Subjects: 010504 meteorology & atmospheric sciences, Meteorology, Aperture synthesis, 0211 other engineering and technologies, Microwave radiometry, Soil Science, airborne campaign, Context (language use), 02 engineering and technology, 01 natural sciences, In situ observations, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Airborne campaign, Computers in Earth Sciences, Transect, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, Microwave radiometer, Geology, in situ observations, Brightness temperature, Environmental science, Satellite, Soil moisture, microwave radiometry, soil moisture, SMOS
Abstract: International audience; The Soil Moisture and Ocean Salinity (SMOS) satellite mission, based on an aperture synthesis L-band radiometer was successfully launched in November 2009. In the context of a validation campaign for the SMOS mission, intensive airborne and in situ observations were performed in southwestern France for the SMOS CAL/VAL, from April to May 2009 and from April to July 2010. The CAROLS (Cooperative Airborne Radiometer for Ocean and Land Studies) bi-angular (34°-0°) and dual-polarized (V and H) L-band radiometer was designed, built and installed on board the French ATR-42 research aircraft. During springs of 2009 and 2010, soil moisture observations from the SMOSMANIA (Soil Moisture Observing System - Meteorological Automatic Network Integrated Application) network of Météo-France were complemented by airborne observations of the CAROLS L-band radiometer, following an Atlantic-Mediterranean transect in southwestern France. Additionally to the 12 stations of the SMOSMANIA soil moisture network, in situ measurements were collected in three specific sites within an area representative of a SMOS pixel. Microwave radiometer observations, acquired over southwestern France by the CAROLS instrument were analyzed in order to assess their sensitivity to surface soil moisture (wg). A combination of microwave brightness temperature (Tb) at either two polarizations or two contrasting incidence angles was used to retrieve wg through regressed empirical logarithmic equations with good results, depending on the chosen configuration. The regressions derived from the CAROLS measurements were applied to the SMOS Tb and their retrieval performance was evaluated. The retrievals of wg showed significant correlation (p-value < 0.05) with surface measurements for most of the SMOSMANIA stations (8 of 12 stations) and with additional field measurements at two specific sites, also. Root mean square errors varied from 0.03 to 0.09 m3m-3 (0.06 m3m-3 on average).
Published: 2011
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374. A combined optical-microwave method to retrieve soil moisture over vegetated areas

Author: Arnaud Mialon, Jean-Christophe Calvet, Cristian Mattar, Clément Albergel, Juan C. Jiménez-Muñoz, Dominique Guyon, P. Richaume, José A. Sobrino, Yann Kerr, Jean-Pierre Wigneron, Nathalie Novello, Department of Thermodynamics, Faculty of Physics, Universitat de València (UV), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), European Centre for Medium-Range Weather Forecasts (ECMWF), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Météo France, Centre National d'Etudes Spatiales (CNES). FRA., Météo-France Direction Interrégionale Sud-Est (DIRSE), Météo-France, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Vegetation optical depth, L band, 010504 meteorology & atmospheric sciences, NDVI, télédétection, 0211 other engineering and technologies, Soil science, 02 engineering and technology, Microwave method, surface temperature, 01 natural sciences, Normalized Difference Vegetation Index, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, LAI, LEAF AREA INDEX, SURFACE TEMPERATURE, SOIL MOISTURE, L-BAND, medicine, Traitement du signal et de l'image, normalized vegetation difference index (NDVI), Electrical and Electronic Engineering, Water content, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Signal and Image processing, soil moisture (SM), Enhanced vegetation index, 15. Life on land, L-band, General Earth and Planetary Sciences, Environmental science, microwave radiometry, medicine.symptom, Vegetation (pathology), [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Microwave
Abstract: A simple approach for correcting for the effect of vegetation in the estimation of the surface soil moisture (wS) from L-band passive microwave observations is presented in this study. The approach is based on semi-empirical relationships between soil moisture and the polarized reflectivity including the effect of the vegetation optical depth which is parameterized as a function of the normalized vegetation difference index (NDVI). The method was tested against in situ measurements collected over a grass site from 2004 to 2007 (SMOSREX experiment). Two polarizations (horizontal/vertical) and five incidence angles (20◦, 30◦, 40◦, 50◦, and 60◦) were considered in the analysis. The best wS estimations were obtained when using both polarizations at an angle of 40◦. The average accuracy in the soil moisture retrievals was found to be approximately 0.06 m3/m3, improving the estimations by 0.02 m3/m3 with respect to the case in which the vegetation effect is not considered. The results indicate that information on vegetation (through a vegetation index such as NDVI) is useful for the estimation of soil moisture through the semi-empirical regressions.
Published: 2011
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375. Evaluation of remotely sensed and modelled soil moisture products using global ground-based in situ observations

Author: Lars Isaksen, Joaquín Muñoz-Sabater, Wolfgang Wagner, C. Gruhier, Yann Kerr, Patricia de Rosnay, S. Hasenauer, and Clément Albergel
Subjects: Meteorology, Anomaly (natural sciences), Biome, Soil Science, Geology, Scatterometer, Numerical weather prediction, Annual cycle, Data assimilation, Environmental science, Satellite, Computers in Earth Sciences, Water content, Remote sensing
Abstract: In situ soil moisture data from more than 200 stations located in Africa, Australia, Europe and the United States are used to determine the reliability of three soil moisture products, one analysis from the ECMWF (European Centre for Medium-Range Weather Forecasts) numerical weather prediction system (SM-DAS-2) and two remotely sensed soil moisture products, namely ASCAT (Advanced scatterometer) and SMOS (Soil Moisture Ocean Salinity). SM-DAS-2 is produced offline at ECMWF and relies on an advanced surface data assimilation system (Extended Kalman Filter) used to optimally combine conventional observations with satellite measurements. ASCAT remotely sensed surface soil moisture is provided in near real time by EUMETSAT. At ECMWF, ASCAT is used for soil moisture analyses in SM-DAS-2, also. Finally the SMOS remotely sensed soil moisture data level two product developed at CESBIO is used. Evaluation of the times series as well as of the anomaly values, shows good performances of the three products to capture surface soil moisture annual cycle and short term variability. Correlations with in situ data are very satisfactory over most of the investigated sites located in contrasted biomes and climate conditions with averaged values of 0.70 for SM-DAS-2, 0.53 for ASCAT and 0.54 for SMOS. Although radio frequency interference disturbs the natural microwave emission of the Earth observed by SMOS in several parts of the world, hence the soil moisture retrieval, performances of SMOS over Australia are very encouraging.
Published: 2011
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376. CAROLS: A New Airborne L-Band Radiometer for Ocean Surface and Land Observations

Author: Jean-Christophe Calvet, Clément Albergel, Joseph Tenerelli, Marion Leduc-Leballeur, Pascal Fanise, Jean-Pierre Wigneron, Antonio Rius, Mehrez Zribi, Monique Dechambre, Mickaël Pardé, Jacquline Boutin, Gilles Reverdin, Niels Skou, Yann Kerr, Ernesto Lopez-Baeza, Sten Schmidl Søbjærg, Danièle Hauser, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technical University of Denmark [Lyngby] (DTU), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Université de Valence, University of Valencia, Institut d'Estudis Espacials de Catalunya (IEEC-CSIC), Collecte Localisation Satellites (CLS), Centre National d'Études Spatiales [Toulouse] (CNES)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), TOSCA/CNES, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Ørsted-DTU, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Universitat de València (UV)
Subjects: analyse de données, L band, 010504 meteorology & atmospheric sciences, Meteorology, télédétection, 0211 other engineering and technologies, Polarimetry, 02 engineering and technology, lcsh:Chemical technology, 01 natural sciences, Biochemistry, RADIOMETER, CAROLS, L-BAND, MISSION SMOS, OCEAN SALINITY, SOIL MOISTURE, MESURE AEROPORTEE, Article, Analytical Chemistry, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, lcsh:TP1-1185, ocean salinity, Electrical and Electronic Engineering, Instrumentation, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, business.industry, Conjunction (astronomy), Ocean salinity, radiometer, L band radiometer, Atomic and Molecular Physics, and Optics, On board, L-band, Autre (Sciences de l'ingénieur), Global Positioning System, Environmental science, Satellite, Soil moisture, soil moisture, business, SMOS
Abstract: The "Cooperative Airborne Radiometer for Ocean and Land Studies" (CAROLS) L-Band radiometer was designed and built as a copy of the EMIRAD II radiometer constructed by the Technical University of Denmark team. It is a fully polarimetric and direct sampling correlation radiometer. It is installed on board a dedicated French ATR42 research aircraft, in conjunction with other airborne instruments (C-Band scatterometer--STORM, the GOLD-RTR GPS system, the infrared CIMEL radiometer and a visible wavelength camera). Following initial laboratory qualifications, three airborne campaigns involving 21 flights were carried out over South West France, the Valencia site and the Bay of Biscay (Atlantic Ocean) in 2007, 2008 and 2009, in coordination with in situ field campaigns. In order to validate the CAROLS data, various aircraft flight patterns and maneuvers were implemented, including straight horizontal flights, circular flights, wing and nose wags over the ocean. Analysis of the first two campaigns in 2007 and 2008 leads us to improve the CAROLS radiometer regarding isolation between channels and filter bandwidth. After implementation of these improvements, results show that the instrument is conforming to specification and is a useful tool for Soil Moisture and Ocean Salinity (SMOS) satellite validation as well as for specific studies on surface soil moisture or ocean salinity.
Published: 2011
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377. Event detection of hydrological processes with passive L-band data from SMOS

Author: Olivier Merlin, Elsa Jacquette, Arnaud Quesney, Yann Kerr, Ahmad Al Bitar, Francois Cabot, Arnaud Mialon, and Philippe Richaume
Subjects: L band, Interferometry, Meteorology, Environmental science, Satellite, Time series, Physical oceanography, Orbital mechanics, Fuzzy logic, Image resolution, Remote sensing
Abstract: Since its launch, the ESAs Soil Moisture and Ocean Sali nity (SMOS) satellite, is delivering new data from its L-Band 1.4Ghz 2D interferometer [1]. The observations from SMOS are used to retrieve soil moisture in the first centimeters and ocean salinity at the su rface of the water. The observations are multi-angular with a 3 days maximum revisit time. The spatial resolution of SMOS data is 40km. In this paper we present on event detection algorithm implemented at CATDS (Centre Aval de Traitement des Donnees SMOS) the CNES level 3 and level 4 SMOS enter. This algorithm is a three stage change detection algorithm. At stage one the possibility/probability of occurrence of the event is evaluated. This is done via spatio-temporal constraints maps. These maps are obtained from the analysis of NSIDCs freezing index products over the last century. Climate data from ancillary files are tested will taking into consideration the uncertainty of the data. Some selected retrieved variables are also tested. At stage two a time series analys is is applied. In the current version of the algorithm a direct change detection algorithm is used . The tests make use of availa ble variables of polarization index, retrieved soil moisture Finally at stage three a simple fuzzy logic approach is used to decide if the event occurred. This approaches takes into consideration the separation time of the data. Ascending and descending orbits are taken into consideration. In this study freezing detection is presented over central CONUS. The temporal and angular signature of SMOS will be presented. Comparison is done with the SCAN network Keywords: SMOS, L-Band, soil moisture, calibrati on/validation, event detection, freeze
Published: 2010
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378. SMOS CATDS level 3 global products over land

Author: Arnaud Quesney, Yann Kerr, Ahmad Al Bitar, Elsa Jacquette, Arnaud Mialon, Philippe Richaume, and Francois Cabot
Subjects: L band, Emissivity, Environmental science, Satellite, Ground segment, Vegetation, Physical oceanography, Albedo, Water content, Remote sensing
Abstract: The Soil Moisture and Ocean Salinity (SMOS) satellite is a 2D interferometer in L-band (1.4 GHz). Over land, it enables to probe the earth surface emissivity related to soil moisture in the first centimeters of the soil, with an aimed accuracy better than 4m 3 .m -3 and an average spatial resolution of 40km. The European Space Agency's (ESA) ground segment provides half-orbit soil moisture products at level 2. The Centre National d'Etudes Spatiales (CNES) in France has developed the CATDS (Centre Aval de Traitement des Donnees SMOS) ground segment in order to produce global maps, known as level 3 and 4 products. Over land, the algorithm is based on the level 2 soil moisture ESA's prototype. The major enhancement of the CATDS concerns the use of multi-orbit retrieval. The level 3 Soil moisture (SM) products are global maps of soil moisture, and other geophysical products (vegetation optical thickness, albedo, soil dielectric constant or surface temperature). For a particular point, the revisit time is between 1 and 3 days, and the entire Earth's surface is covered by SMOS field of view in 3 days. Level 3 SM products are available over different time periods. First, a 1 day global product is generated for each day. Then, 1 day global maps are aggregated in 3-day global products, 10- day and monthly products.
Published: 2010
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379. Disaggregation as a top-down approach for evaluating 40 km resolution SMOS data using point-scale measurements: application to AACES-1

Author: Arnaud Mialon, Christoph Rudiger, Yann Kerr, Ahmad Al Bitar, Philippe Richaume, Jeffrey P. Walker, and Olivier Merlin
Subjects: Correlation coefficient, Meteorology, Remote sensing (archaeology), Calibration, Environmental science, Satellite, Moderate-resolution imaging spectroradiometer, Physical oceanography, Scale (map), Remote sensing, Downscaling
Abstract: The SMOS (Soil Moisture and Ocean Salinity) satellite provides soil moisture data at about 40 km resolution globally. Validation of SMOS data using in situ measurements is complicated due to the large integrated scale of remote sensing observations. Nevertheless, different approaches can be used to circumvent the direct comparison. One is to upscale ground measurements using aggregation rules. Another is to downscale (or disaggregate) remote sensing data at the representativeness scale of ground measurements. This study combines both approaches to make ground and remote sensing data match at an intermediate spatial scale. On one hand, the local-scale in situ soil moisture data collected during the first AACES (Australian Airborne Calibration/validation Experiments for SMOS) are aggregated to 4 km resolution. On the other hand, a disaggregation methodology of SMOS data based on 1 km resolution MODIS (MODerate resolution Imaging Spectroradiometer) data is implemented at 4 km resolution over the Murrumbidgee catchment, the site of the AACES campaign. Results indicate a correlation coefficient between disaggregated and ground observations of 0.92. The y-intercept of the linear regression between disaggregated and ground observations is very close to 0. However, the slope of that line is 0.44 only. This seems to highlight an issue with either the dielectric constant model or the roughness parameter value currently used in the SMOS retrieval algorithm.
Published: 2010
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380. First evaluation of SMOS observations and Level-2 products over agricultural sites in temperate regions

Author: Jean-Pierre Wigneron, Yann Kerr, Arnaud Mialon, Nathalie Novello, François Cabot, Steven Delwart, François Demontoux, Maria-José Escorihuela, Ferrazzoli, P., Ajit Govind, Jennifer Grant, Dominique Guyon, Elsa Jacquette, Heather Lawrence, Ernesto Lopez-Baeza, Ali Mahmoodi, Cristian Mattar, Susanne Mecklenburg, Christophe Moisy, Monerris, S., Rahmoune, R., Philippe Richaume, Patricia de Rosnay, Rüdiger, C., Kauzar Saleh, Mike Schwank, Sobrino, Jose A., Philippe Waldteufel, Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), isardSAT, Università degli Studi di Roma Tor Vergata [Roma], Universitat de València (UV), Array Systems Computing, Partenaires INRAE, ESA Centre for Earth Observation (ESRIN), Barcelona Expert Centre, European Centre for Medium-Range Weather Forecasts (ECMWF), Monash University [Clayton], Department of Geography [Cambridge, UK], University of Cambridge [UK] (CAM), Institut Fédéral de Recherches sur la Forêt, la Neige et le Paysage (WSL), Institut Fédéral de Recherches [Suisse], ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Agence Spatiale Européenne = European Space Agency (ESA), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, MISSION SMOS, [SDE]Environmental Sciences, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2010

381. First evaluation of SMOS observations and L2 soil moisture products over a variety of biomes at global scale

Author: Jean Pierre Wigneron, Novello, N., Yann Kerr, Cabot, F., Delwart, S., François Demontoux, Govind, A., Guyon, D., Jacquette, E., Heather Lawrence, Lopez-Baeza, E., Mahmoodi, A., Mattar, C., Mecklenburg, S., Arnaud Mialon, Christophe Moisy, Khaldoun Saleh, Richaume, P., Schwank, M., Sobrino, J., Philippe Waldteufel, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Université de Valence, University of Valencia, Array Systems, University of Toronto, Global Change Unit, European Space Research Institute (ESRIN), Swiss Federal Institute for Forest, Snow and Avalanche Research WSL, ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Agence Spatiale Européenne = European Space Agency (ESA), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), and Universitat de València (UV)
Subjects: [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, commissioning phase, L2 products, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, soil moisture, Smos
Abstract: International audience; The SMOS (Soil Moisture and Ocean Salinity) mission was launched on November 2, 2009. It is the second Earth Explorer Opportunity mission to be developed as part of ESA's Living Planet Programme. It aims to improve our understanding of the Earth's water cycle by making global observations of soil moisture over land and salinity over oceans. Over the land surfaces, SMOS will advance our understanding of the exchange processes between the Earth's surface and atmosphere, and will have many applications to improve weather and climate models and in areas such as agriculture and water resource management. Over the land surfaces, the principle of the SMOS Level 2 retrieval algorithm is to exploit multi-angular data in order to retrieve simultaneously several surface parameters including surface soil moisture (SM) and vegetation characteristics. The L-MEB (L-band Microwave Emission of the Biosphere) forward model was selected to simulate the microwave signatures of the various soil and vegetation types which are present in the mixed SMOS pixel, which is larger than about 30 x 30 km generally. The study presented in this paper was carried out in the framework of this assessment process over the land surfaces. Preliminary analyses evaluating the Smos observations in terms of Brightness Temperatures (TB) and L2 products (mainly soil moisture SM and vegetation optical depth) were carried out over several sites at global scale.
Published: 2010

382. Disaggregation of MODIS surface temperature over an agricultural area using a time series of Formosat-2 images

Author: Ghani Chehbouni, Benoît Coudert, Gérard Dedieu, J. Garatuza, Frédéric Jacob, Olivier Merlin, Benoît Duchemin, Olivier Hagolle, Yann Kerr, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'étude des interactions entre sols, agrosystèmes et hydrosystèmes (LISAH), Institut National de la Recherche Agronomique (INRA), Instituto Tecnologico de Sonora, ITSON, Yaqui experiment, FP6, PLEIADeS, PNTS, CNES program TOASC, European Project, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), European Project: 36381,PLEIADES, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
Subjects: Albedo, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, Soil Science, 02 engineering and technology, 01 natural sciences, Normalized Difference Vegetation Index, Scaling, ASTER, Advanced Spaceborne Thermal Emission and Reflection Radiometer, Disaggregation, Satellite imagery, Computers in Earth Sciences, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Formosat-2, Geology, Enhanced vegetation index, Vegetation, Surface temperature, MODIS, Photosynthetically active radiation, Environmental science, Moderate-resolution imaging spectroradiometer, Shortwave, Vegetation fraction
Abstract: No of Pages 13; International audience; The temporal frequency of the thermal data provided by current spaceborne high-resolution imagery systems is inadequate for agricultural applications. As an alternative to the lack of high-resolution observations, kilometric thermal data can be disaggregated using a green (photosynthetically active) vegetation index e.g. NDVI (Normalized Difference Vegetation Index) collected at high resolution. Nevertheless, this approach is only valid in the conditions where vegetation temperature is approximately uniform. To extend the validity domain of the classical approach, a new methodology is developed by representing the temperature difference between photosynthetically and non-photosynthetically active vegetation. In practice, both photosynthetically and non-photosynthetically active vegetation fractions are derived from a time series of Formosat-2 shortwave data, and then included in the disaggregation procedure. The approach is tested over a 16 km by 10 km irrigated cropping area in Mexico during a whole agricultural season. Kilometric MODIS (MODerate resolution Imaging Spectroradiometer) surface temperature is disaggregated at 100 m resolution, and disaggregated temperature is subsequently compared against concurrent ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data. Statistical results indicate that the new methodology is more robust than the classical one, and is always more accurate when fractional non-photosynthetically active vegetation cover is larger than 0.10. The mean correlation coefficient and slope between disaggregated and ASTER temperature is increased from 0.75 to 0.81 and from 0.60 to 0.77, respectively. The approach is also tested using the MODIS data re-sampled at 2 km resolution. Aggregation reduces errors in MODIS data and consequently increases the disaggregation accuracy.
Published: 2010
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383. An improved algorithm for disaggregating microwave-derived soil moisture based on red, near-infrared and thermal-infrared data

Author: Jeffrey P. Walker, Yann Kerr, Ahmad Al Bitar, Olivier Merlin, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Civil and Environmental Engineering, The University of Melbourne, University of Melbourne, SMOS, NAFE, Université de Melbourne, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Evaporation, Soil Science, Nonlinear, 01 natural sciences, NAFE, Disaggregation, Downscaling, 14. Life underwater, Computers in Earth Sciences, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, Water content, 0105 earth and related environmental sciences, Remote sensing, Geology, 04 agricultural and veterinary sciences, Vegetation, 15. Life on land, MODIS, Soil water, 040103 agronomy & agriculture, Potential evaporation, 0401 agriculture, forestry, and fisheries, Environmental science, Plant cover, Spatial variability, Moderate-resolution imaging spectroradiometer, Soil moisture, SMOS
Abstract: No of Pages 12; International audience; Accurate high-resolution soil moisture data are needed for a range of agricultural and hydrologic activities. To improve the spatial resolution of ∼40 km resolution passive microwave-derived soil moisture, a methodology based on 1 km resolution MODIS (MODerate resolution Imaging Spectroradiometer) red, near-infrared and thermal-infrared data has been implemented at 4 km resolution. The three components of that method are (i) fractional vegetation cover, (ii) soil evaporative efficiency (defined as the ratio of actual to potential evaporation) and (iii) a downscaling relationship. In this paper, 36 different disaggregation algorithms are built from 3 fractional vegetation cover formulations, 3 soil evaporative efficiency models, and 4 downscaling relationships. All algorithms differ with regard to the representation of the nonlinear relationship between microwave-derived soil moisture and optical-derived soil evaporative efficiency. Airborne L-band data collected over an Australian agricultural area are used to both generate ∼40 km resolution microwave pixels and verify disaggregation results at 4 km resolution. Among the 36 disaggregation algorithms, one is identified as being more robust (insensitive to soil, vegetation and atmospheric variables) than the others with a mean slope between MODIS-disaggregated and L-band derived soil moisture of 0.94. The robustness of that algorithm is notably assessed by comparing the disaggregation results obtained using composited (averaged) Terra and Aqua MODIS data, and using data from Terra and Aqua separately. The error on disaggregated soil moisture is systematically reduced by compositing daily Terra and Aqua data with an error of 0.012 vol./vol.
Published: 2010
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384. The SMOS mission: new tool for monitoring key elements of the global water cycle

Author: Jordi Font, Jean-Pierre Wigneron, Mark R. Drinkwater, Nicolas Reul, Jacqueline Boutin, Philippe Waldteufel, Manuel Martin-Neira, Yann Kerr, Maria-José Escorihuela, C. Gruhier, S. Juglea, Susanne Mecklenburg, Francois Cabot, Achim Hahne, Steven Delwart, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), isardSAT, department of hydrology, Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), IFREMER (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), European Space Research Institute (ESRIN), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Agence Spatiale Européenne = European Space Agency (ESA), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL)
Subjects: L band, 010504 meteorology & atmospheric sciences, Meteorology, 0207 environmental engineering, Soil Moisture and Ocean Salinity, Field of view, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, 7. Clean energy, 01 natural sciences, Vegetation water content, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Sea surface salinity, Electrical and Electronic Engineering, 020701 environmental engineering, 0105 earth and related environmental sciences, Remote sensing, vegetation water content, Radiometer, sea surface salinity (SSS), Sampling (statistics), SSS, L-band, Sea surface temperature, Geography, Soil Moisture and Ocean Salinity (SMOS), Interferometry, 13. Climate action, Brightness temperature, Radiometry, Soil moisture, soil moisture, SMOS
Abstract: Kerr, Y. ... et al.-- 22 pages, 9 figures, 3 tables.-- © 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works, It is now well understood that data on soil moisture and sea surface salinity (SSS) are required to improve meteorological and climate predictions. These two quantities are not yet available globally or with adequate temporal or spatial sampling. It is recognized that a spaceborne L-band radiometer with a suitable antenna is the most promising way of fulfilling this gap. With these scientific objectives and technical solution at the heart of a proposed mission concept the European Space Agency (ESA) selected the Soil Moisture and Ocean Salinity (SMOS) mission as its second Earth Explorer Opportunity Mission. The development of the SMOS mission was led by ESA in collaboration with the Centre National d'Etudes Spatiales (CNES) in France and the Centro para el Desarrollo Tecnologico Industrial (CDTI) in Spain. SMOS carries a single payload, an L-Band 2-D interferometric radiometer operating in the 14001427-MHz protected band. The instrument receives the radiation emitted from Earth's surface, which can then be related to the moisture content in the first few centimeters of soil over land, and to salinity in the surface waters of the oceans. SMOS will achieve an unprecedented maximum spatial resolution of 50 km at L-band over land (43 km on average over the field of view), providing multiangular dual polarized (or fully polarized) brightness temperatures over the globe. SMOS has a revisit time of less than 3 days so as to retrieve soil moisture and ocean salinity data, meeting the mission's science objectives. The caveat in relation to its sampling requirements is that SMOS will have a somewhat reduced sensitivity when compared to conventional radiometers. The SMOS satellite was launched successfully on November 2, 2009, The contributions came obviously from the science teams but also from the technical teams at Agencies (ESA and CNES) and in the Industry (mainly CASA EADS, Thales Alenia Space, and Eurockot, but also many others). The French contribution was supported also by the national program TOSCA
Published: 2010
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385. SMOS: The Challenging Sea Surface Salinity Measurement From Space

Author: Jordi Font, Jacqueline Boutin, Achim Hahne, Nicolas Reul, Yann Kerr, Manuel Martin-Neira, Andrés Borges, Adriano Camps, Susanne Mecklenburg, Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universitat Politècnica de Catalunya [Barcelona] (UPC), Construcciones aeronauticas S.A., European aeronautic, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Space Research Institute (ESRIN), Agence Spatiale Européenne = European Space Agency (ESA), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: 010504 meteorology & atmospheric sciences, Meteorology, 0211 other engineering and technologies, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, 01 natural sciences, Space exploration, Physics::Geophysics, salinity, remote sensing, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Astrophysics::Solar and Stellar Astrophysics, Electrical and Electronic Engineering, Water cycle, Physics::Atmospheric and Oceanic Physics, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Aperture synthesis, Ocean chemistry, Microwave radiometer, Astrophysics::Instrumentation and Methods for Astrophysics, imaging, Salinity, Microwave imaging, Environmental science, Radiometry, Satellite, microwave radiometry
Abstract: 17 pages, 10 figures.-- © 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works, Soil Moisture and Ocean Salinity, European Space Agency, is the first satellite mission addressing the challenge of measuring sea surface salinity from space. It uses an L-band microwave interferometric radiometer with aperture synthesis (MIRAS) that generates brightness temperature images, from which both geophysical variables are computed. The retrieval of salinity requires very demanding performances of the instrument in terms of calibration and stability. This paper highlights the importance of ocean salinity for the Earth's water cycle and climate; provides a detailed description of the MIRAS instrument, its principles of operation, calibration, and image-reconstruction techniques; and presents the algorithmic approach implemented for the retrieval of salinity from MIRAS observations, as well as the expected accuracy of the obtained results
Published: 2010
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386. L-band emission of rough surfaces: Comparison between experimental data and different modeling approaches

Author: Tzong-Dar Wu, Heather Lawrence, Jianchen Shi, François Demontoux, Arnaud Mialon, Valery Mironov, Liang Chen, Jean-Pierre Wigneron, Yann Kerr, Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Université Sciences et Technologies - Bordeaux 1, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Electrical Engineering (DEE), National Taiwan Ocean University (NTOU), Russian Academy of Sciences [Moscow] (RAS), Institute for Computational Earth System Science (ICESS), University of California [Santa Barbara] (UCSB), University of California-University of California, Université Sciences et Technologies - Bordeaux 1 (UB), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), University of California [Santa Barbara] (UC Santa Barbara), and University of California (UC)-University of California (UC)
Subjects: SOIL-LITTER STRUCTURES, télédétection, [SDV]Life Sciences [q-bio], [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, Context (language use), 02 engineering and technology, Method of moments (statistics), Physics::Geophysics, ELECTROMAGNETIC SCATTERING BY ROUGH SURFACES, MICROWAVE EMISSIVITY, NUMERICAL SIMULATION, SMOS MISSION, symbols.namesake, 0202 electrical engineering, electronic engineering, information engineering, Surface roughness, Emissivity, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 021101 geological & geomatics engineering, Remote sensing, Physics, Computer simulation, HFSS, Mathematical analysis, 020206 networking & telecommunications, Finite element method, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Maxwell's equations, 13. Climate action, [SDE]Environmental Sciences, symbols
Abstract: International audience; In this paper we present a study of a numerical modeling approach based on the Finite Element Method (FEM) for the prediction of rough surface emission at L-band, including a comparison with other modeling approaches and experimental data. The numerical approach relies on the use of ANSYS' numerical computation software HFSS (High Frequency Structure Simulator), which in turn solves Maxwell's equations directly using the Finite Element Method. It is useful in the context of the SMOS (Soil Moisture and Ocean Salinity) mission since it can be extended to model the scattering and emission of heterogeneous media including complex multilayer systems such as the radiometric L-band emission of soil and litter layers in forests. In this paper we firstly validate the approach by comparing predictions of rough surface scattering against the Method of Moments (MoM). Secondly we study the accuracy of the numerical approach by comparing results of rough surface emissivity against measurements and predictions of the Advanced Integral Equation Method (AIEM).
Published: 2010
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387. Radio frequency interferences investigation using the airborne L-band full polarimetric radiometer CAROLS

Author: Jacqueline Boutin, Monique Dechambre, Mehrez Zribi, Mickaël Pardé, Nicolas Reul, Joseph Tenerelli, Pascal Fanise, Yann Kerr, Danièle Hauser, ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Collecte Localisation Satellites (CLS), Centre National d'Études Spatiales [Toulouse] (CNES)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Brightness, L band, Radiometer, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, Polarimetry, 02 engineering and technology, 01 natural sciences, Electromagnetic interference, Geography, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Kurtosis, Radiometry, Radio frequency, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing
Abstract: International audience; In the present paper, different methods are proposed for the detection and mitigation of the undesirable effects of radio frequency interference (RFI) in microwave radiometry. The first of these makes use of kurtosis to detect the presence of non-Gaussian signals, whereas the second imposes a threshold on the standard deviation of brightness temperatures, in order to distinguish natural emission variations from RFI. Finally, the third approach is based on the use of a threshold applied to the third and fourth Stokes parameters. All of these methods have been applied and tested, with a CAROLS radiometer operating in the L-band, on data acquired during airborne campaigns made in spring 2009 over the South West of France. The performance of each, or of two combined approaches is analyzed with our database. We thus show that the kurtosis method is well adapted to pulsed RFI, whereas the method based on the second moment is well adapted to continuous-wave RFI.
Published: 2010
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388. CAROLS campaigns 2009: First Results

Author: Clément Albergel, Danièle Hauser, Jean-Christophe Calvet, Jacqueline Boutin, Gilles Reverdin, Mehrez Zribi, Mickaël Pardé, Yann Kerr, K. Saleh, Arnaud Mialon, Monique Dechambre, A. Ruis, Jean-Pierre Wigneron, M. Crapeau, E. Lopez Baeza, Pascal Fanise, ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), SSE 2010, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB)
Subjects: business.product_category, 010504 meteorology & atmospheric sciences, Meteorology, [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, 02 engineering and technology, 01 natural sciences, law.invention, Airplane, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, law, Radar, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, business.industry, Storm, Scatterometer, Sea surface temperature, Geography, Global Positioning System, Radiometry, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: International audience; The CAROLS, L band radiometer, is built and designed as a copy of EMIRAD II radiometer of DTU team. It is a Correlation radiometer with direct sampling and fully polarimetric (i.e 4 Stockes). It will be used in conjunction with other airborne instruments (in particular the C-Band scatterometer (STORM) and IEEEC GPS system, Infrared CIMEL radiometer and one visible camera), in coordination with in situ field campaigns for SMOS CAL/VAL. The instruments are implemented on board the French research airplane ATR42. A scientific campaign with thirteen flights is realized over south-western France, Valencia site and Bay of Biscay (Atlantic Ocean) in spring 2009. In order to qualify the radiometer data, different types of aircraft movements were realized: circle flights, wing and nose wags. Simultaneously to flights, different ground measurements were made over continental surfaces and ocean. Results show a good quality of data. For continental surfaces, important Radio-Frequency Interferences (RFI) were observed over a large part of the studied region
Published: 2010
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389. Soil moisture active and passive microwave products: intercomparison and evaluation over a Sahelian site

Author: E. G. Njoku, Wolfgang Wagner, P. de Rosnay, S. Hasenauer, Eric Mougin, Mehrez Zribi, R.A.M. de Jeu, Thomas R. H. Holmes, Yann Kerr, F. Timouk, C. Gruhier, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Centre for Medium-Range Weather Forecasts (ECMWF), Institute of Photogrammetry and Remote Sensing, Faculty of Earth and Life Sciences, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), NASA-California Institute of Technology (CALTECH), and Hydrology and Geo-environmental sciences
Subjects: 010504 meteorology & atmospheric sciences, Soil Moisture, [SDE.MCG]Environmental Sciences/Global Changes, 0207 environmental engineering, Soil science, 02 engineering and technology, Monsoon, Spatial distribution, Mali, 01 natural sciences, lcsh:Technology, lcsh:TD1-1066, Passive Microwaves, Sahel, Intercomparison, lcsh:Environmental technology. Sanitary engineering, 020701 environmental engineering, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Water content, lcsh:Environmental sciences, 0105 earth and related environmental sciences, Remote sensing, lcsh:GE1-350, Moisture, TMI, lcsh:T, lcsh:Geography. Anthropology. Recreation, AMSR-E, lcsh:G, Soil water, Spatial ecology, Environmental science, Satellite, AMMA, ERS, Microwave, SMOS
Abstract: This paper presents a comparison and an evaluation of five soil moisture products based on satellite-based passive and active microwave measurements. Products are evaluated for 2005–2006 against ground measurements obtained from the soil moisture network deployed in Mali (Sahel) in the framework of the African Monsoon Multidisciplinary Analysis project. It is shown that the accuracy of the soil moisture products is sensitive to the retrieval approach as well as to the sensor type (active or passive) and to the signal frequency (from 5.6 GHz to 18.8 GHz). The spatial patterns of surface soil moisture are compared between the different products at meso-scale (14.5° N–17.5° N and 2° W–1° W). A general good consistency between the different satellite soil moisture products is shown in terms of meso-scale spatial distribution, in particular after convective rainfall occurrences. Soil moisture values provided by the different products are compared to ground measurements time series. Although soil moisture products obtained from satellite generally over-estimate soil moisture values during the dry season, most of them capture soil moisture temporal variations in good agreement with ground station measurements.
Published: 2010
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390. Comparison of Two Bare Soil Reflectivity Models and Validation with L-Band Radiometer Measurements

Author: Arnaud Mialon, Mike Schwank, P. de Rosnay, Jean-Pierre Wigneron, Yann Kerr, C. Matzler, Ingo Völksch, Institut Fédéral de Recherches sur la Forêt, la Neige et le Paysage (WSL), Institut Fédéral de Recherches [Suisse], Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institute of Applied Physics [Bern] (IAP), University of Bern, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Centre for Medium-Range Weather Forecasts (ECMWF), and 0 Pre-GFZ, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum
Subjects: Materials science, 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Soil science, 550 - Earth sciences, 02 engineering and technology, Surface finish, 01 natural sciences, Physics::Geophysics, Root mean square, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Emissivity, Surface roughness, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, electromagnetic scattering by rough surfaces, permittivity, Correlation function (statistical mechanics), Roughness length, Brightness temperature, Soil water, General Earth and Planetary Sciences, microwave radiometry, soil moisture, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: The emission of bare soils at microwave L-band (1-2 GHz) frequencies is known to be correlated with surface soil moisture. Roughness plays an important role in determining soil emissivity although it is not clear which roughness length scales are most relevant. Small-scale (i.e., smaller than the resolution limit) inhomogeneities across the soil surface and with soil depth caused by both spatially varying soil properties and topographic features may affect soil emissivity. In this paper, roughness effects were investigated by comparing measured brightness temperatures of well-characterized bare soil surfaces with the results from two reflectivity models. The selected models are the air-to-soil transition model and Shi's parameterization of the integral equation model (IEM). The experimental data taken from the Surface Monitoring of the Soil Reservoir Experiment (SMOSREX) consist of surface profiles, soil permittivities and temperatures, and brightness temperatures at 1.4 GHz with horizontal and vertical polarizations. The types of correlation functions of the rough surfaces were investigated as required to evaluate Shi's parameterization of the IEM. The correlation functions were found to be clearly more exponential than Gaussian. Over the experimental period, the diurnal mean root mean square (rms) height decreased, while the correlation length and the type of correlation function did not change. Comparing the reflectivity models with respect to their sensitivities to the surface rms height and correlation length revealed distinct differences. Modeled reflectivities were tested against reflectivities derived from measured brightness, which showed that the two models perform differently depending on the polarization and the observation angle.
Published: 2010
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391. MODELING THE EFFECT OF SURFACE ROUGHNESS ON THE BACK-SCATTERING COEFFICIENT AND EMISSIVITY OF A SOIL-LITTER MEDIUM USING A NUMERICAL MODEL

Author: Heather Lawrence, François Demontoux, Tzong-Dar Wu, Yann Kerr, Pierre Borderies, Jiancheng Shi, P. Paillou, Jean-Pierre Wigneron, Liang Chen, Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Electrical Engineering National Taiwan Ocean University, National Taiwan Ocean University (NTOU), ONERA - The French Aerospace Lab [Palaiseau], ONERA, Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Institute for Computational Earth System Science [Santa Barbara] (ICESS), University of California [Santa Barbara] (UCSB), University of California-University of California, CNES, Région Aquitaine - CEMT (Electromagnetic caracterisation and remote sensing), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and ONERA-Université Paris Saclay (COmUE)
Subjects: Materials science, Backscatter, business.industry, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Numerical analysis, [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, 020206 networking & telecommunications, Context (language use), [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, Dielectric, Method of moments (statistics), Finite element method, Computational physics, Physics::Geophysics, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Optics, 0202 electrical engineering, electronic engineering, information engineering, Emissivity, Surface roughness, business, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 021101 geological & geomatics engineering
Abstract: International audience; In the context of the SMOS mission, a new numerical method based on the finite element method is presented which can be used to model the radiometric L-band emission of soil and litter layers in forests. Many different characteristics of these layers that affect the soil-litter emission can be incorporated into the model, including surface roughness, inclusions and volume effects. Soil moisture is incorporated into the model as a function of the dielectric permittivity constant. The model is validated for a single dielectric layer with a surface roughness of Gaussian autocorrelation function by comparing results of the backscattering coefficient with those calculated by the 2D method of moments. Good general agreement is obtained between these results. An emissivity calculation for a single layer rough surface is also presented and compared with the emissivity of a flat layer.
Published: 2009

392. AMMA Land Surface Model Intercomparison Experiment coupled to the Community Microwave Emission Model: ALMIP-MEM

Author: Aaron Boone, Bertrand Decharme, Thierry Pellarin, P. de Rosnay, Jean-Pierre Wigneron, Jan Polcher, Yann Kerr, Phil Harris, Matthias Drusch, Gianpaolo Balsamo, European Centre for Medium-Range Weather Forecasts (ECMWF), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Unité écologie fonctionnelle et physique de l'environnement, Institut National de la Recherche Agronomique (INRA), ECMWF and the European Space Agency (ESA) under the contract 20244/07/I-LG, the European Community's Sixth Framework Research Programme, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Atmospheric Science, Brightness, 010504 meteorology & atmospheric sciences, Opacity, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, 0207 environmental engineering, Soil Science, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, Astrophysics::Cosmology and Extragalactic Astrophysics, Aquatic Science, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Oceanography, 01 natural sciences, land surface modeling, Atmosphere, remote sensing, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Radiative transfer, 020701 environmental engineering, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Remote sensing, Radiometer, Ecology, Paleontology, Forestry, Geophysics, 13. Climate action, Space and Planetary Science, Brightness temperature, Environmental science, Satellite, soil moisture, Microwave
Abstract: International audience; This paper presents the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Models Intercomparison Project (ALMIP) for Microwave Emission Models (ALMIP-MEM). ALMIP-MEM comprises an ensemble of simulations of C-band brightness temperatures over West Africa for 2006. Simulations have been performed for an incidence angle of 55°, and results are evaluated against C-band satellite data from the Advanced Microwave Scanning Radiometer on Earth Observing System (AMSR-E). The ensemble encompasses 96 simulations, for 8 Land Surface Models (LSMs) coupled to 12 configurations of the Community Microwave Emission Model (CMEM). CMEM has a modular structure which permits combination of several parameterizations with different vegetation opacity and soil dielectric models. ALMIP-MEM provides the first intercomparison of state-of-the-art land surface and microwave emission models at regional scale. Quantitative estimates of the relative importance of land surface modeling and radiative transfer modeling for the monitoring of low-frequency passive microwave emission on land surfaces are obtained. This is of high interest for the various users of coupled land surface microwave emission models. Results show that both LSMs and microwave model components strongly influence the simulated top of atmosphere (TOA) brightness temperatures. For most of the LSMs, the Kirdyashev opacity model is the most suitable to simulate TOA brightness temperature in best agreement with the AMSR-E data. When this best microwave modeling configuration is used, all the LSMs are able to reproduce the main temporal and spatial variability of measured brightness temperature. Averaged among the LSMs, correlation is 0.67 and averaged normalized standard deviation is 0.98.
Published: 2009
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393. Effect of dew on the radiometric signal over a grass field at L-band

Author: M. J. Escorihuela, Yann Kerr, K. Saleh, Jean-Pierre Wigneron, P. de Rosnay, Jean-Christophe Calvet, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Centre for Medium-Range Weather Forecasts (ECMWF), Department of geography, University of Cambridge [UK] (CAM), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), Centre national de recherches météorologiques (CNRM), and Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Planetary boundary layer, [SDV]Life Sciences [q-bio], 0211 other engineering and technologies, 02 engineering and technology, MOISTURE, Atmospheric sciences, 01 natural sciences, RADIOMETRY, 14. Life underwater, Electrical and Electronic Engineering, MICROWAVE, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Moisture, 15. Life on land, Geotechnical Engineering and Engineering Geology, Atmospheric temperature, RELATION SOL-ATMOSPHERE, Salinity, SOIL, Dew point, 13. Climate action, Brightness temperature, [SDE]Environmental Sciences, Environmental science, Dew
Abstract: International audience; The future Soil Moisture and Ocean Salinity satellite time of overpass is 6 A.m. and 6 P.M. at the equator. In many regions, morning dew is expected at the time of the satellite overpass and might play a role in soil moisture retrievals. The aim of this study was to assess the effects of dew on L-band measurements. Radiometric, biomass, and dew measurements were performed over a natural grass field. Our results show that at the diurnal scale, vegetation internal water content changes play a major role in emission. A direct impact of dew on measurements was not identified. However, a brightness temperature increase of 0.5 and 1 K was observed at vertical and horizontal polarizations' respectively. This increase was detected later after dew, suggesting that it was not directly caused by the presence of dew on the grass blades. Our hypothesis is that the observed increase in brightness temperatures is due to the absorption of dew water by the litter layer.
Published: 2009
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394. A sequential model for disaggregating near-surface soil moisture observations using multi-resolution thermal sensors

Author: Jeffrey P. Walker, Olivier Merlin, Yann Kerr, Ahmad Al Bitar, Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Civil and Environmental Engineering [Melbourne], University of Melbourne, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Soil Science, 02 engineering and technology, 01 natural sciences, NAFE, Scaling, ASTER, Disaggregation, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Computers in Earth Sciences, Aster (genus), Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, Pixel, biology, Resolution (electron density), Geology, biology.organism_classification, Multi-sensor, Spectroradiometer, MODIS, 13. Climate action, Soil water, Environmental science, Soil moisture, Fractal, Downscaling, SMOS
Abstract: A sequential model is developed to disaggregate microwave-derived soil moisture from 40 km to 4 km resolution using MODIS (Moderate Imaging Spectroradiometer) data and subsequently from 4 km to 500 m resolution using ASTER (Advanced Scanning Thermal Emission and Reflection Radiometer) data. The 1 km resolution airborne data collected during the three-week National Airborne Field Experiment 2006 (NAFE'06) are used to simulate the 40 km pixels, and a thermal-based disaggregation algorithm is applied using 1 km resolution MODIS and 100 m resolution ASTER data. The downscaled soil moisture data are subsequently evaluated using a combination of airborne and in situ soil moisture measurements. A key step in the procedure is to identify an optimal downscaling resolution in terms of disaggregation accuracy and sub-pixel soil moisture variability. Very consistent optimal downscaling resolutions are obtained for MODIS aboard Terra, MODIS aboard Aqua and ASTER, which are 4 to 5 times the thermal sensor resolution. The root mean square error between the 500 m resolution sequentially disaggregated and ground-measured soil moisture is 0.^062 vol./vol. with a bias of −0.045^ vol./vol. and values ranging from 0.08 to 0.40^ vol./vol.
Published: 2009
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395. Soil moisture retrievals at L-band using a two-step inversion approach (COSMOS/NAFE'05 Experiment)

Author: Gilles Boulet, Philippe Maisongrande, Khaldoun Saleh, M. J. Escorihuela, Jeffrey P. Walker, Rocco Panciera, Steven Delwart, Jean-Pierre Wigneron, P. Wursteisen, Yann Kerr, Philippe Richaume, University of Cambridge [UK] (CAM), Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Civil and Environmental Engineering [Melbourne], University of Melbourne, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Civil and Environmental Engineering, Department of Civil and Environment, Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: L band, 010504 meteorology & atmospheric sciences, Soil texture, 0211 other engineering and technologies, Soil Science, 02 engineering and technology, 01 natural sciences, NAFE, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Surface roughness, Soil roughness COSMOS, Computers in Earth Sciences, Radiometry, Water content, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Radiometer, Geology, 15. Life on land, L-band, Brightness temperature, Soil water, Environmental science, Soil moisture, SMOS
Abstract: COSMOS (Campaign for validating the Operation of Soil Moisture and Ocean Salinity), and NAFE (National Airborne Field Experiment) were two airborne campaigns held in the Goulburn River catchment (Australia) at the end of 2005. These airborne measurements are being used as benchmark data sets for validating the SMOS (Soil Moisture and Ocean Salinity) ground segment processor over prairies and crops. This paper presents results of soil moisture inversions and brightness temperature simulations at different resolutions from dual-polarisation and multi-angular L-band (1.4 GHz) measurements obtained from two independent radiometers. The aim of the paper is to provide a method that could overcome the limitations of unknown surface roughness for soil moisture retrievals from L-band data. For that purpose, a two-step approach is proposed for areas with low to moderate vegetation. Firstly, a two-parameter inversion of surface roughness and optical depth is used to obtain a roughness correction dependent on land use only. This step is conducted over small areas with known soil moisture. Such roughness correction is then used in the second step, where soil moisture and optical depth are retrieved over larger areas including mixed pixels. This approach produces soil moisture retrievals with root mean square errors between 0.034 m3 m−3 and 0.054 m3 m−3 over crops, prairies, and mixtures of these two land uses at different resolutions.
Published: 2009
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396. Soil moisture remote sensing for numerical weather prediction: L-band emission modeling over land surfaces, the community microwave emission model (CMEM)

Author: Thomas R. H. Holmes, Yann Kerr, P. de Rosnay, Jean-Christophe Calvet, Christoph Rudiger, Matthias Drusch, Jean-Pierre Wigneron, Gianpaolo Balsamo, Aaron Boone, European Centre for Medium-Range Weather Forecasts (ECMWF), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Institut National de la Recherche Agronomique (INRA), VU University Amsterdam, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU)
Subjects: Brightness, L band, 010504 meteorology & atmospheric sciences, C band, [SDV]Life Sciences [q-bio], MISSION SMOS, 0211 other engineering and technologies, Weather forecasting, Astrophysics::Cosmology and Extragalactic Astrophysics, 02 engineering and technology, Atmospheric model, Numerical weather prediction, Atmospheric sciences, computer.software_genre, 01 natural sciences, Sea surface temperature, 13. Climate action, Brightness temperature, [SDE]Environmental Sciences, Environmental science, computer, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing
Abstract: The community microwave emission model (CMEM) is the low frequency forward observation operator developed at ECMWF. It is used in this paper to simulate brightness temperatures at local and regional scales over SMOSREX (France) and AMMA (West Africa), respectively. Background errors in simulated brightness temperatures are quantified at different frequencies and incidence angles for these two sites.
Published: 2008
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397. Evaluation of AMSR-E soil moisture product based on ground measurements over temperate and semi-arid regions

Author: C. Gruhier, Eric Ceschia, Eric Mougin, P. Richaume, P. de Rosnay, Jean-Christophe Calvet, and Yann Kerr
Subjects: Radiometer, 010504 meteorology & atmospheric sciences, Meteorology, 0207 environmental engineering, 02 engineering and technology, Monsoon, Numerical weather prediction, Atmospheric sciences, 01 natural sciences, Arid, 6. Clean water, Geophysics, 13. Climate action, Soil water, Temperate climate, General Earth and Planetary Sciences, Environmental science, Radiometric dating, 020701 environmental engineering, Water content, 0105 earth and related environmental sciences
Abstract: Soil moisture (SM) products provided by remote sensing approaches at continental scale are of great importance for land surface modeling and numerical weather prediction. Before using remotely sensed SM products it is crucial to validate them. This paper presents an evaluation of AMSR-E (Advanced Microwave Scanning Radiometer - Earth Observing System) SM products over two sites. They are located in the south-west of France and in the Sahelian part of Mali in West Africa, in the framework of the SMOSREX (Surface Monitoring Of Soil Reservoir Experiment) and AMMA (African Monsoon Multidisciplinary Analysis) projects respectively. The most representative station of the four stations of each site is used for the comparison of AMSR-E derived and in-situ SM measurements in absolute and normalized values. Results suggest that, although AMSR-E SM product is not able to capture absolute SM values, it provides reliable information on surface SM temporal variability, at seasonal and rainy event scale. It is shown, however, that the use of radiometric products, such as polarization ratio, provides better agreement with ground stations than the derived SM products.
Published: 2008
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398. Radiative transfer solution for rugged and heterogeneous scene observations

Author: Xavier Briottet, Francois Cabot, Christophe Miesch, and Yann Kerr
Subjects: business.industry, Computer science, Materials Science (miscellaneous), Monte Carlo method, Irradiance, Industrial and Manufacturing Engineering, Spatial heterogeneity, Optics, Atmospheric radiative transfer codes, Radiance, Radiative transfer, Satellite, Business and International Management, business, Divergence (statistics), Optical depth, Remote sensing
Abstract: A physical algorithm is developed to solve the radiative transfer problem in the solar reflective spectral domain. This new code, Advanced Modeling of the Atmospheric Radiative Transfer for Inhomogeneous Surfaces (AMARTIS), takes into account the relief, the spatial heterogeneity, and the bidirectional reflectances of ground surfaces. The resolution method consists of first identifying the irradiance and radiance components at ground and sensor levels and then modeling these components separately, the rationale being to find the optimal trade off between accuracy and computation times. The validity of the various assumptions introduced in the AMARTIS model are checked through comparisons with a reference Monte Carlo radiative transfer code for various ground scenes: flat ground with two surface types, a linear sand dune landscape, and an extreme mountainous configuration. The results show a divergence of less than 2% between the AMARTIS code and the Monte Carlo reference code for the total signals received at satellite level. In particular, it is demonstrated that the environmental and topographic effects are properly assessed by the AMARTIS model even for situations in which the effects become dominant.
Published: 2008

399. Monte Carlo approach for solving the radiative transfer equation over mountainous and heterogeneous areas

Author: Francois Cabot, Christophe Miesch, Yann Kerr, and Xavier Briottet
Subjects: business.industry, Materials Science (miscellaneous), Monte Carlo method, Monte Carlo method for photon transport, Industrial and Manufacturing Engineering, Hybrid Monte Carlo, Atmospheric radiative transfer codes, Optics, Photon transport in biological tissue, Dynamic Monte Carlo method, Monte Carlo method in statistical physics, Business and International Management, business, Geology, Remote sensing, Monte Carlo molecular modeling
Abstract: An algorithm based on the Monte Carlo method is developed to solve the radiative transfer equation in the reflective domain (0.4-4 microm) of the solar spectrum over rugged terrain. This algorithm takes into account relief, spatial heterogeneity, and ground bidirectional reflectance. The method permits the computation of irradiance components at ground level and radiance terms reaching an airborne or satelliteborne sensor. The Monte Carlo method consists of statistically simulating the paths of photons inside the Earth-atmosphere system to reproduce physical phenomena while introducing neither analytical modeling nor assumption. The potentialities of the code are then depicted over different types of landscape, including a seashore, a desert region, and a steep mountainous valley.
Published: 2008

400. Flagging the Topographic Impact on the SMOS Signal

Author: F. Secherre, Yann Kerr, L. Coret, Jean-Pierre Wigneron, Arnaud Mialon, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Aeronautic Defence and Space Company (EADS), Écologie fonctionnelle et physique de l'environnement (EPHYSE), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Brightness, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, MISSION SMOS, 0211 other engineering and technologies, 02 engineering and technology, 01 natural sciences, Physics::Geophysics, Emissivity, 14. Life underwater, Electrical and Electronic Engineering, Digital elevation model, Variogram, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, L-band passive microwave, Moisture, Pixel, topography impact on passive microwave, [INFO.INFO-IA]Computer Science [cs]/Computer Aided Engineering, Brightness temperature, General Earth and Planetary Sciences, Environmental science, Scale (map), SMOS
Abstract: International audience; Soil moisture retrieval models from the Soil Moisture and Ocean Salinity (SMOS) mission, which is an L-band microwave interferometer, are based on multiangular measurements and make use of the emissivity angular signature. Mountainous areas modify local incidence angles, implying significant impacts on brightness temperatures and, consequently, on soil moisture retrievals. The purpose of this paper is to establish a criterion in quantifying the relevance of topographic impacts at the SMOS scale ( ~ 40 km). The goal is thus to define a method of flagging the pixels according to the relative impact of topography on the brightness temperature. The proposed method uses the variogram of digital elevation model images. As a result, a map of the pixels to be flagged is produced to ensure that no soil moisture retrievals are carried out on pixels that are affected by strong topographic effects. As validation, a model was also used to simulate differences between brightness temperature variations between mountainous areas and flat surfaces.
Published: 2008
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