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51. Spatial and temporal variability of land CO 2 fluxes estimated with remote sensing and analysis data over western Eurasia

Author

Lafont, Sébastien, Kergoat , Laurent, Dedieu, Gérard, Chevillard, Anne, Karstens, Ute, Kolle, Olaf, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), 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-Saclay-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2002
Full Text
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52. Correcting satellite and airborne reflectance from atmospheric noise: consequences on vegetation characteristics estimates

Author

Launay, M., Guerif, Martine, Dedieu, Gérard, Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and ProdInra, Migration

Subjects
[SDV] Life Sciences [q-bio], [SDE] Environmental Sciences, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2001

53. Assimilation of optical satellite observations into a coupled canopy functioning and SVAT model

Author

Moulin, Sophie, Kergoat, Laurent, Cayrol, Pascale, Dedieu, Gérard, Prevot, Laurent, Unité d'agronomie de Laon-Péronne, Institut National de la Recherche Agronomique (INRA), Laboratoire d'Ecologie Terrestre (LET), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Unité de bioclimatologie, and IEEE Geoscience and Remote Sensing Society (GRSS). USA.

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences
Published
2000

54. Using a coupled canopy functioning and SVAT model in the ReSeDA experiment: Assimilation of SPOT/HRV observations into the model

Author

Moulin, Sophie, Kergoat, Laurent, Cayrol, Pascale, Dedieu, Gérard, Prevot, Laurent, Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Ecologie Terrestre (LET), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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), Unité de bioclimatologie, Institut National de la Recherche Agronomique (INRA), Université de Toulouse (UT)-Université de Toulouse (UT)-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
modèle svat, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2000

55. STEM-VGT: satellite measurements and terrestrial ecosystem modeling using VEGETATION instrument

Author

Dedieu, Gérard, Lafont , Sébastien, Cayrol, Pascale, Chehbouni, Abdelghani, Kergoat, Laurent, Maisongrande, Philippe, Watts, C., Berthelot, Béatrice, Gérard, Jean-Claude, François, L., Graetz, Dean, Ruimy, Anne, Moulin, Sophie, Saugier, Bernard, Centre National d’Etudes Spatiales, Office de la Recherche Scientifique et Technique Outre Mer (ORSTOM), Universidad de Sonora (USON), Université de Liège, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), and Université Paris-Sud - Paris 11 (UP11)

Subjects
écosystème terrestre, [SDV]Life Sciences [q-bio], satellite, ComputingMilieux_MISCELLANEOUS, modélisation
Abstract

International audience

Published
2000

56. Controlling vegetation growth models with satellite measurements

Author

Kergoat , Laurent, Moulin, Sophie, Cayrol, Pascale, Dedieu, Gérard, Laboratoire d'Ecologie Terrestre (LET), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-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 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-Centre National de la Recherche Scientifique (CNRS), 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
croissance végétale, [SDV]Life Sciences [q-bio], donnée satellitaire, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2000

57. Calibrating a coupled SVAT - vegetation growth model with remotely sensed reflectance and surface temperature : a case study for the HAPEX - Sahel grassland sites

Author

Cayrol, Pascale, Kergoat , Laurent, Moulin, Sophie, Dedieu, Gérard, Chehbouni, Ghani, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement, and Partenaires INRAE

Subjects
evapotranspiration, field, wetness data, sparse crops, heating rates, avhrr data, soil-moisture, atmospheric mesoscale model, multispectral satellite data, [SDV]Life Sciences [q-bio]
Abstract

International audience; Models simulating the seasonal growth of vegetation have been recently coupled to soil-vegetation-atmosphere transfer schemes (SVATS). Such coupled vegetation-SVATS models (V-S) account for changes of the vegetation leaf area index (LAI) over time. One problem faced by V-S models is the high number of parameters that are required to simulate different sites or large areas. Therefore, efficient calibration procedures are needed. This study describes an attempt to calibrate a V-S model with satellite [Advanced Very High Resolution Radiometer (AVHRR)] data in the shortwave and longwave domains. A V-S model is described using ground data collected over three semiarid grassland sites during the Hydrological Atmospheric Pilot Experiment (HAPEX)-Sahel experiment. The effect of calibrating model parameters with time series of normalized difference vegetation index (NDVI) and thermal infrared (TIR) data is assessed by examining the simulated latent heat flux (LE) and LAI for a suite of calibration experiments. A sensitivity analysis showed that the parameters related to plant growth vigor and to soil evaporative resistance were the best candidates for calibration. The NDVI and TIR time series were used to calibrate these parameters, both independently and simultaneously, to assess their synergy. Ground-based, airborne, and satellite sensor (AVHRR) data were successively investigated. Both airborne and AVHRR NDVI data could be used to constrain the vegetation growth vigor. These calibrations significantly improved the simulation of the LAI and LE (rmse decreased by 21% for LE), and the site-to-site variability was greatly enhanced. The soil resistance could also be calibrated with ground-based TIR data, but the effect on the simulated variables was small. Although both NDVI and ground-based TIR data were suitable to constrain the V-S model, the synergy between the two wavelengths was not clearly established. Last, satellite TIR data from the AVHRR proved unsuitable for model calibration. Indeed, the AVHRR surface temperature values were systematically lower than both ground-based data and model outputs. The authors conclude that the calibration of a vegetation-SVAT model with shortwave AVHRR time series can be used to scale the energy and water fluxes up to the regional scale.

Published
2000
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58. Estimation of heat and momentum fluxes over complex terrain using a large aperture scintillometer

Author

Chehbouni, Ghani, Watts, C., Lagouarde, Jean-Pierre, Kerr, Yann H., Rodriguez, J.C., Bonnefond, J.M., Santiago, F., Dedieu, Gérard, Goodrich, D.C., Unkrich, C., Unité de bioclimatologie, Institut National de la Recherche Agronomique (INRA), and ProdInra, Migration

Subjects
MOMENT, EXPERIENCE SALSA, [SDV.SA.SF]Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry, [SDV.SA.SF] Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2000

59. Calibrating a coupled SVAT / vegetation growth model with remotely sensed reflectance and surface temperature: A case study for the HAPEX-Sahel and SALSA grassland sites

Author

Cayrol, Pascale, Kergoat , Laurent, Chehbouni, Ghani, Moulin, Sophie, Dedieu, Gérard, Centre National d’Etudes Spatiales, 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), American Geophysical Union (AGU). USA., 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
hapex sahel, modèle svat, télédétection, [SDV]Life Sciences [q-bio], prairie, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
1999

60. Net primary production estimation over an agricultural area

Author

Moulin, Sophie, Bondeau, Alberte, Dedieu, Gérard, 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), 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
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
1999

61. Utilisation d'un modèle de correction atmosphérique (SMAC) pour le calcul de réflectances au sol à partir d'images Spot

Author

Launay, M., Guerif, Martine, Dedieu, Gérard, Unité de bioclimatologie, Institut National de la Recherche Agronomique (INRA), and ProdInra, Migration

Subjects
[SDV] Life Sciences [q-bio], [SDE] Environmental Sciences, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, ENVIRONNEMENT SPATIAL, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
1999

62. Using atmospheric correction to obtain reflectances from airborne images

Author

Launay, M., Guerif, Martine, Dedieu, Gérard, Unité d'Agronomie de Laon-Péronne ( LILL LAON AGRO), Institut National de la Recherche Agronomique (INRA), and ProdInra, Migration

Subjects
[SDV] Life Sciences [q-bio], [SDE] Environmental Sciences, RAYONNEMENT ELECTROMAGNETIQUE, [SDV]Life Sciences [q-bio], IMAGERIE, [SDE]Environmental Sciences
Abstract

*INRA laboratoire d'agronomie rue Fernand Christ 02007 Laon cedex Diffusion du document : INRA laboratoire d'agronomie rue Fernand Christ 02007 Laon cedex; National audience

Published
1999

63. The coupling of process models and remotely sensed data assimilation for regional modeling (upscaling)

Author

Dedieu, Gérard, Cayrol, Pascale, Kergoat, Laurent, Moulin, Sophie, Centre National de la Recherche Scientifique (CNRS), and VITO. BEL.

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, vegetation functioning, remote sensing, modeling, assimilation technique, télédétection, surface foliaire, Agricultural sciences, activité photosynthétique, forêt, croissance des arbres, Sciences agricoles, ComputingMilieux_MISCELLANEOUS, modélisation
Abstract

International audience

Published
1998

64. Assimilation of multi-sensor and multi-temporal remote sensing data to monitor vegetation and soil : the Alpilles-ReSeDA project

Author

Prevot, Laurent, Baret, Frédéric, Chanzy, Andre, Olioso, Albert, Wigneron, Jean-Pierre, Autret, Hervé, Baudin, Francois, Bessemoulin, Pierre, BETHENOD, Olivier, Blamont, D., Blavoux, B., Bonnefond, Jean-Marc, Boubkraoui, S., Bouman, B.A.M., Braud, Laura, Bruguier, N., Calvet, Jean-Christophe, Caselles, V., Chauki, H., Clevers, J.G.P.W., Coll, C., Company, A., Courault, Dominique, Dedieu, Gérard, Degenne, Pascal, Moulin, Sophie, Lagouarde, Jean-Pierre, Unité de bioclimatologie, Institut National de la Recherche Agronomique (INRA), Unité de Science du Sol, Unité de recherches en bioclimatologie, and Centre National d’Etudes Spatiales

Subjects
modèle de culture, bilan énergétique, suivi de cultures, prévision de rendement, télédétection, [SDE.MCG]Environmental Sciences/Global Changes, Signal and Image processing, Traitement du signal et de l'image, bilan hydrique, Milieux et Changements globaux, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, sol agricole, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
1998
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65. Radiometric normalization of high spatial resolution multi-temporal imagery : A comparison between a relative method and atmospheric correction

Author

El Hajj, Mahmoud, Rumeau, M., Bégué, Agnès, Hagolle, Olivier, Dedieu, Gérard, El Hajj, Mahmoud, Rumeau, M., Bégué, Agnès, Hagolle, Olivier, and Dedieu, Gérard

Abstract

Radiometric normalization is a vital stage in the pre-processing of multi-temporal imagery. It aims to insure a reliable exploitation of images acquired under different imaging conditions. In this study, we investigate whether a relative normalization can replace atmospheric correction. The investigation was done using a time series of eighteen SPOT 5 images acquired over Reunion Island and intended to be used for sugarcane monitoring. An automatic method for relative normalization is introduced, and its results are compared to atmospherically corrected data. The relative method is based on the reflectances of invariant targets (IT) that are selected automatically. The atmospheric correction is carried out by the 6S code. The comparison was performed a) by using a set of manually selected invariant targets (MSIT), and b) by assessing the NDVI behavior of a set of sugarcane fields. An excellent correlation is obtained between relatively and atmospherically corrected data: the coefficient of determination (R2) is higher than 0.96 for all spectral bands and for the NDVI. Moreover, a comparable impact is observed on the temporal profiles of MSIT and on the NDVI trajectories of sugarcane field.

Published
2007

66. Assimilation of optical satellite data into a crop process model: interannual study

Author

Moulin, Sophie, Dedieu, Gérard, Fischer, Alberte, 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
[SDV]Life Sciences [q-bio], satellite, donnée satellitaire, ComputingMilieux_MISCELLANEOUS, culture
Abstract

National audience

Published
1997

67. Satellite measurements and vegetation models for global carbon cycle studies

Author

Dedieu, Gérard, Ruimy, Anne, Maisongrande, Philippe, Kergoat , Laurent, Moulin, Sophie, Saugier, Bernard, Centre National d’Etudes Spatiales, 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), 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
cycle du carbone, [SDV]Life Sciences [q-bio], satellite, végétation, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
1997

68. Some views on possible approaches to test and improve vgetation net primary productivity models

Author

Dedieu, Gérard, Kergoat , Laurent, Maisongrande, Philippe, Ruimy, Anne, Saugier, Bernard, Frison, Pierre-Louis, Moulin, Sophie, Mougin, Éric, Mognard-Campbell, N., 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 Paris-Sud - Paris 11 (UP11), European Geophysical Society (EGS). DEU., 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
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
1996

70. The MISTIGRI thermal infrared project: scientific objectives and mission specifications

Author

Lagouarde, Jean-Pierre, primary, Bach, Michel, additional, Sobrino, José A., additional, Boulet, Gilles, additional, Briottet, Xavier, additional, Cherchali, Selma, additional, Coudert, Benoit, additional, Dadou, Isabelle, additional, Dedieu, Gérard, additional, Gamet, Philippe, additional, Hagolle, Olivier, additional, Jacob, Frédéric, additional, Nerry, Françoise, additional, Olioso, Albert, additional, Ottlé, Catherine, additional, Roujean, Jean-louis, additional, and Fargant, Guy, additional

Published
2012
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71. Assimilation of short wavelength remote sensing observations within a crop model: methodological development and interannual field scale study

Author

Moulin, Sophie, Fischer, Alberte, Dedieu, Gérard, 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), 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
modèle de culture, [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, télédétection, donnée satellite, Sciences agricoles, ComputingMilieux_MISCELLANEOUS, Agricultural sciences, parcelle agricole
Abstract

National audience

Published
1995

72. Coupling of satellite data and production models for yields forecasting at regional scale. State of art and methodological developments

Author

Fischer, Alberte, Moulin, Sophie, Dedieu, Gérard, gu, x. f., GUYOT, Gérard, Guerif, Martine, DELECOLLE, Richard, Baret, Frédéric, Laboratoire d'Etudes et de Recherches en Teledetection Spatiale, Partenaires INRAE, Unité de bioclimatologie, and Institut National de la Recherche Agronomique (INRA)

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
1995

74. Extracting SoilWater Holding Capacity Parameters of a Distributed Agro-Hydrological Model from High Resolution Optical Satellite Observations Series.

Author

Ferrant, Sylvain, Bustillo, Vincent, Burel, Enguerrand, Salmon-Monviola, Jordy, Claverie, Martin, Jarosz, Nathalie, Tiangang Yin, Rivalland, Vincent, Dedieu, Gérard, Demarez, Valerie, Ceschia, Eric, Probst, Anne, Al-Bitar, Ahmad, Kerr, Yann, Probst, Jean-Luc, Durand, Patrick, and Gascoin, Simon

Subjects
SOIL moisture, AGROHYDROLOGY, HIGH resolution imaging, ARTIFICIAL satellites, LEAF area index
Abstract

Sentinel-2 (S2) earth observation satellite mission, launched in 2015, is foreseen to promote within-field decisions in Precision Agriculture (PA) for both: (1) optimizing crop production; and (2) regulating environmental impacts. In this second scope, a set of Leaf Area Index (LAI) derived from S2 type time-series (2006-2010, using Formosat-2 satellite) is used to spatially constrain the within-field crop growth and the related nitrogen contamination of surface water simulated at a small experimental catchment scale with the distributed agro-hydrological model Topography Nitrogen Transfer and Transformation (TNT2). The Soil Water Holding Capacity (SWHC), represented by two parameters, soil depth and retention porosity, is used to fit the yearly maximum of LAI (LAX) at each pixel of the satellite image. Possible combinations of soil parameters, defining 154 realistic SWHC found on the study site are used to force spatially homogeneous SWHC. LAX simulated at the pixel level for the 154 SWHC, for each of the five years of the study period, are recorded and hereafter referred to as synthetic LAX. Optimal SWHCyear_I,pixel_j, corresponding to minimal difference between observed and synthetic LAXyear_I,pixel_j, is selected for each pixel, independent of the value at neighboring pixels. Each re-estimated soil maps are used to re-simulate LAXyear_I. Results show that simulated and synthetic LAXyear_I,allpixels obtained from SWHCyear_I,allpixels are close and accurately fit the observed LAXyear_I,allpixels (RMSE = 0.05 m²/m² to 0.2 and R² = 0.99 to 0.94), except for the year 2008 (RMSE = 0.8 m²/m² and R² = 0.8). These results show that optimal SWHC can be derived from remote sensing series for one year. Unique SWHC solutions for each pixel that limit the LAX error for the five years to less than 0.2 m²/m² are found for only 10% of the pixels. Selection of unique soil parameters using multi-year LAX and neighborhood solution is expected to deliver more robust soil parameters solutions and need to be assessed further. The use of optical remote sensing series is then a promising calibration step to represent crop growth within crop field at catchment level. Nevertheless, this study discusses the model and data improvements that are needed to get realistic spatial representation of agro-hydrological processes simulated within catchments. [ABSTRACT FROM AUTHOR]

Published
2016
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75. Spatialising crop models

Author

Faivre, Robert, primary, Leenhardt, Delphine, additional, Voltz, Marc, additional, Benoît, Marc, additional, Papy, François, additional, Dedieu, Gérard, additional, and Wallach, Daniel, additional

Published
2004
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85. The MISTIGRI thermal infrared project: scientific objectives and mission specifications.

Author

Lagouarde, Jean-Pierre, Bach, Michel, Sobrino, JoséA., Boulet, Gilles, Briottet, Xavier, Cherchali, Selma, Coudert, Benoit, Dadou, Isabelle, Dedieu, Gérard, Gamet, Philippe, Hagolle, Olivier, Jacob, Frédéric, Nerry, Françoise, Olioso, Albert, Ottlé, Catherine, Roujean, Jean-louis, and Fargant, Guy

Subjects
IMAGE processing, METROPOLITAN areas, CLIMATE change, ARTIFICIAL satellites
Abstract

This article presents the MISTIGRI project of a microsatellite developed by the French space agency Centre National d'Etudes Spatiales (CNES) in cooperation with Spain (Image Processing Laboratory of the University of Valencia and Centro para el Desarrollo Tecnológico Industrial (CDTI)). MISTIGRI is a mission that has the originality of combining a high spatial resolution (∼50 m) with a daily revisit in the thermal infrared (TIR). MISTIGRI is an experimental mission devoted to demonstrate the potential of such TIR data for future operational missions. The scientific goals and expected applications of the mission are described: they encompass the monitoring of (i) agricultural areas and related hydrological processes, (ii) urban areas, and (iii) coastal areas and continental waters. Then, the specifications on spatial resolution, revisit frequency, overpass time, and spectral configuration are justified. The strategy of the mission is based on the combination with a network of long-term experimental sites. It will also make possible observing some areas facing rapid climatic change. The choice of the orbit is presented. Finally, we give rapid overviews of both the instrumental concept and the proposed mission architecture. [ABSTRACT FROM PUBLISHER]

Published
2013
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88. The Impacts of Spatial Resolution, Viewing Angle, and Spectral Vegetation Indices on the Quantification of Woody Mediterranean Species Seasonality Using Remote Sensing.

Author

Elbaz, Shelly, Sheffer, Efrat, Lensky, Itamar M., Levin, Noam, Karnieli, Arnon, Dedieu, Gérard, and Hagolle, Olivier

Subjects
REMOTE sensing, REMOTE-sensing images, VEGETATION mapping, PLANT species, SPECIES, VEGETATION patterns, WOODY plants
Abstract

Discriminating between woody plant species using a single image is not straightforward due to similarity in their spectral signatures, and limitations in the spatial resolution of many sensors. Seasonal changes in vegetation indices can potentially improve vegetation mapping; however, for mapping at the individual species level, very high spatial resolution is needed. In this study we examined the ability of the Israel/French satellite of VENμS and other sensors with higher spatial resolutions, for identifying woody Mediterranean species, based on the seasonal patterns of vegetation indices (VIs). For the study area, we chose a site with natural and highly heterogeneous vegetation in the Judean Mountains (Israel), which well represents the Mediterranean maquis vegetation of the region. We used three sensors from which the indices were derived: a consumer-grade ground-based camera (weekly images at VIS-NIR; six VIs; 547 individual plants), UAV imagery (11 images, five bands, seven VIs) resampled to 14, 30, 125, and 500 cm to simulate the spatial resolutions available from some satellites, and VENμS Level 1 product (with a nominal spatial resolution of 5.3 m at nadir; seven VIs; 1551 individual plants). The various sensors described seasonal changes in the species' VIs at different levels of success. Strong correlations between the near-surface sensors for a given VI and species mostly persisted for all spatial resolutions ≤125 cm. The UAV ExG index presented high correlations with the ground camera data in most species (pixel size ≤125 cm; 9 of 12 species with R ≥ 0.85; p < 0.001), and high classification accuracies (pixel size ≤30 cm; 8 species with >70%), demonstrating the possibility for detailed species mapping from space. The seasonal dynamics of the species obtained from VENμS demonstrated the dominant role of ephemeral herbaceous vegetation on the signal recorded by the sensor. The low variance between the species as observed from VENμS may be explained by its coarse spatial resolution (effective ground spatial resolution of 7.5) and its non-nadir viewing angle (29.7°) over the study area. However, considering the challenging characteristics of the research site, it may be that using a VENμS type sensor (with a spatial resolution of ~1 m) from a nadir point of view and in more homogeneous and dense areas would allow for detailed mapping of Mediterranean species based on their seasonality. [ABSTRACT FROM AUTHOR]

Published
2021
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89. Impact of doubled CO2on global‐scale leaf area index and evapotranspiration: Conflicting stomatal conductance and LAI responses

Author

Kergoat, Laurent, Lafont, Sébastien, Douville, Hervé, Berthelot, Béatrice, Dedieu, Gérard, Planton, Serge, and Royer, Jean‐François

Abstract

Current increase in atmospheric CO2is expected to modify both climate and plant function, thereby impacting plant structure and gas exchange. We investigate the effects of doubled CO2on leaf area index (LAI) and evapotranspiration (ETR) using a global vegetation model for present‐day and doubled‐CO2conditions. The model assumes that adaptation of plants to the local climate leads to an equilibrium LAI, which depends on resource availability (minimizing water stress, canopy carbon cost and self‐shading). The model compares reasonably well with remote sensing estimates of LAI. Four doubled‐CO2simulations are designed to investigate the role of climate, CO2‐induced stomatal closure, enhanced photosynthesis, and a combination of these effects. These simulations show that plant physiological responses to doubled CO2are potentially more important than climate changes for LAI, and equally important for ETR. In addition, even the sign of the simulated changes in LAI and ETR varies with the assumptions on plant responsiveness to CO2. A reduction of stomatal conductance moderates or cancels the water losses caused by a warmer and drier climate, but photosynthesis stimulation counteracts this stomatal effect, especially in the mid‐to‐high latitudes, because of enhanced LAI. Experimental evidence of LAI and ETR response to CO2has been reviewed and compared to the different simulations. On the basis of this confrontation we argue that plant response to CO2doubling may have a relatively small net impact on global ETR and may cause a moderate increase of LAI. Tree stomata may be less responsive to CO2than was previously assumed, and stimulated plant growth partly cancels the water savings caused by stomatal closure. Understanding the responses of plant canopies to CO2is therefore critical for land surface hydrology in a CO2rich world.

Published
2002
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90. Relative Radiometric Normalization and Atmospheric Correction of a SPOT 5 Time Series.

Author

El Hajj M, Bégué A, Lafrance B, Hagolle O, Dedieu G, and Rumeau M

Abstract

Multi-temporal images acquired at high spatial and temporal resolution are an important tool for detecting change and analyzing trends, especially in agricultural applications. However, to insure a reliable use of this kind of data, a rigorous radiometric normalization step is required. Normalization can be addressed by performing an atmospheric correction of each image in the time series. The main problem is the difficulty of obtaining an atmospheric characterization at a given acquisition date. In this paper, we investigate whether relative radiometric normalization can substitute for atmospheric correction. We develop an automatic method for relative radiometric normalization based on calculating linear regressions between unnormalized and reference images. Regressions are obtained using the reflectances of automatically selected invariant targets. We compare this method with an atmospheric correction method that uses the 6S model. The performances of both methods are compared using 18 images from of a SPOT 5 time series acquired over Reunion Island. Results obtained for a set of manually selected invariant targets show excellent agreement between the two methods in all spectral bands: values of the coefficient of determination (r²) exceed 0.960, and bias magnitude values are less than 2.65. There is also a strong correlation between normalized NDVI values of sugarcane fields (r² = 0.959). Despite a relative error of 12.66% between values, very comparable NDVI patterns are observed.

Published
2008
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