7 results on '"Petitcolin, Francois"'
Search Results
2. Validation of a new parametric model for atmospheric correction of thermal infrared data
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Ellicott, Evan, Vermote, Eric, Petitcolin, Francois, and Hook, Simon J.
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Remote sensing -- Analysis ,Business ,Earth sciences ,Electronics and electrical industries - Abstract
Surface temperature is a key component for understanding energy fluxes between the Earth's surface and atmosphere. Accurate retrieval of surface temperature from satellite observations requires proper correction of the thermal channels for atmospheric emission and attenuation. Although the split-window method has offered relatively accurate measurements, this empirical approach requires in situ data and will only perform well if the in situ data are from the same surface type and similar climatology. Single channel correction reduces uncertainty inherent to the split-window method, but requires an accurate radiative transfer model and description of the atmospheric profile. Unfortunately, this method is impractical for operational correction of satellite retrievals due to the size of data sets and computation time required by radiative transfer modeling. We present a thermal parametric model based upon the MODTRAN radiative transfer code and tuned to Moderate Resolution Imaging Spectrometer (MODIS) channels. Comparison with MODTRAN showed a good performance for the parametric model and computation speeds approximately three orders of magnitude faster. Sea surface temperature (SST) calculated using atmospheric correction parameters generated from our model showed consistent results (rmse = 0.49 K) and small bias (-0.45 K) with the MODIS SST product (MYD28). Validation of surface temperatures derived using our model with in situ land and water temperature measurements exhibited accuracy (mean bias < 0.35 K) and low error (rmse < 1 K) for MODIS bands 31 and 32. Finally, an investigation of profile sources and their effect on atmospheric correction offered insight into the application of the parametric model for operational correction of MODIS thermal bands. Index Terms--Parametric modeling, remote sensing, temperature.
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- 2009
3. Overview of the SMOS sea surface salinity prototype processor
- Author
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Zine, Sonia, Boutin, Jacqueline, Font, Jordi, Reul, Nicolas, Waldteufel, Philippe, Gabarro, Carolina, Tenerelli, Joseph, Petitcolin, Francois, Vergely, Jean-Luc, Talone, Marco, and Delwart, Steven
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Soil moisture -- Analysis ,Earth temperature -- Observations ,Oceanography -- Research ,Salinity -- Observations ,Business ,Earth sciences ,Electronics and electrical industries - Abstract
The L-band interferometric radiometer onboard the Soil Moisture and Ocean Salinity mission will measure polarized brightness temperatures (Tb). The measurements are affected by strong radiometric noise. However, during a satellite overpass, numerous measurements are acquired at various incidence angles at the same location on the Earth's surface. The sea surface salinity (SSS) retrieval algorithm implemented in the Level 2 Salinity Prototype Processor (L2SPP) is based on an iterative inversion method that minimizes the differences between Tb measured at different incidence angles and Tb simulated by a full forward model. The iterative method is initialized with a first-guess surface salinity that is iteratively modified until an optimal fit between the forward model and the measurements is obtained. The forward model takes into account atmospheric emission and absorption, ionospheric effects (Faraday rotation), scattering of celestial radiation by the rough ocean surface, and rough sea surface emission as approximated by one of three models. Potential degradation of the retrieval results is indicated through a flagging strategy. We present results of tests of the L2SPP involving horizontally uniform scenes with no disturbing factors (such as sun glint or land proximity) other than wind-induced surface roughness. Regardless of the roughness model used, the error on the retrieved SSS depends on the location within the swath and ranges from 0.5 psu at the center of the swath to 1.7 psu at the edge, at 35 psu and 15 [degrees]C. Dual-polarization (DP) mode provides a better correction for wind-speed (WS) biases than pseudofirst Stokes mode (ST1). For a WS bias of -1 m. [s.sup.-1], the corresponding SSS bias at the center of the swath is equal to -0.3 psu in DP mode and to -0.5 psu in ST1 mode. The inversion methodology implicitly assumes that WS errors follow a Gaussian distribution, even though these errors should follow more closely a Rayleigh distribution. For this reason, the use of wind components, which typically exhibit Gaussian error distributions, may be preferred in the retrieval. However, the use of noisy wind components creates WS and SSS biases at low WSs (0.1 psu at 3 m [s.sup.-l]). At a sea surface temperature (SST) of 15 [degrees]C, the retrieved SSS is weakly sensitive to the SST biases, with the SSS bias always lower than 0.3 psu for SST biases ranging from --0.5 [degrees]C to --2 [degrees]C. In DP mode, biases in the vertical total electron content (TEC) of the atmosphere result in SSS biases smaller than 0.2 psu. The pseudofirst Stokes mode is insensitive to TEC. Failure to fully account for sea surface roughness scattering effects in the computation of sky radiation contribution leads to a maximum SSS bias of 0.2 psu in the selected configuration, i.e., a descending orbit over the Northern Pacific in February. To achieve SSS biases that are smaller than 0.2 psu, special care must be taken to correct for biases at low WS and to ensure that the bias on the mean WS (averaged over 200 km x 200 km and ten days) remains smaller than 0.5 m [s.sup.-1]. Index Terms--Microwave radiometry, oceanography, salinity.
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- 2008
4. SMOS: Objectives and Approach for Ocean Salinity Observations
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Font, Jordi, Boutin, Jacqueline, Reul, Nicolas, Spurgeon, Paul, Ballaberea, Joaquim, Chuprin, Andrei, Gabarro, Carolina, Gourrion, Jerome, Hénocq, Claire, Lavender, Samantha, Martin, Nicolas, Martinez, Justino, Mcculloch, Michael, Meirold-Mautner, Ingo, Petitcolin, Francois, Portabella, Marcos, Sabia, Roberto, Talone, Marco, Tenerelli, Joe, Turiel, Antonio, Vergely, Jean-Luc, Waldteufel, Philippe, Yin, Xiaobin, Zine, Sonia, Delwart, Steven, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), 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), 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), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), Collecte Localisation Satellites (CLS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), and Université Grenoble Alpes (UGA)
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[SDU]Sciences of the Universe [physics] - Abstract
International audience; SMOS (Soil Moisture and Ocean Salinity), launched in November 2, 2009 is the first satellite mission addressing the salinity measurement from space through the use of MIRAS (Microwave Imaging Radiometer with Aperture Synthesis), a new two-dimensional interferometer designed by the European Space Agency (ESA) and operating at L-band. This paper presents a summary of the sea surface salinity retrieval approach implemented in SMOS, as well as first results obtained after completing the mission commissioning phase in May 2010. A large number of papers have been published about salinity remote sensing and its implementation in the SMOS mission. An extensive list of references is provided here, many authored by the SMOS ocean salinity team, with emphasis on the different physical processes that have been considered in the SMOS salinity retrieval algorithm.
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- 2010
5. Remote sensing of the terrestrial environment using middle infrared radiation (3.0–5.0 µm)
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Boyd, Doreen S., primary and Petitcolin, Francois, additional
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- 2004
- Full Text
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6. Comparison of land surface emissivity and radiometric temperature derived from MODIS and ASTER sensors
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Jacob, Frédéric, primary, Petitcolin, Franc̨ois, additional, Schmugge, Thomas, additional, Vermote, Éric, additional, French, Andrew, additional, and Ogawa, Kenta, additional
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- 2004
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7. Modeling and Inversion in Thermal Infrared Remote Sensing over Vegetated Land Surfaces.
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Shunlin Liang, Jacob, Frédéric, Schmugge, Thomas, Olioso, Albert, French, Andrew, Courault, Dominique, Ogawa, Kenta, Petitcolin, Francois, Chehbouni, Ghani, Pinheiro, Ana, and Privette, Jeffrey
- Abstract
Thermal Infra Red (TIR) Remote sensing allows spatializing various land surface temperatures: ensemble brightness, radiometric and aerodynamic temperatures, soil and vegetation temperatures optionally sunlit and shaded, and canopy temperature profile. These are of interest for monitoring vegetated land surface processes: heat and mass exchanges, soil respiration and vegetation physiological activity. TIR remote sensors collect information according to spectral, directional, temporal and spatial dimensions. Inferring temperatures from measurements relies on developing and inverting modeling tools. Simple radiative transfer equations directly link measurements and variables of interest, and can be analytically inverted. Simulation models allow linking radiative regime to measurements. They require indirect inversions by minimizing differences between simulations and observations, or by calibrating simple equations and inductive learning methods. In both cases, inversion consists of solving an ill-posed problem, with several parameters to be constrained from few information. Brightness and radiometric temperatures have been inferred by inverting simulation models and simple radiative transfer equations, designed for atmosphere and land surfaces. Obtained accuracies suggest refining the use of spectral and temporal information, rather than innovative approaches. Forthcoming challenge is recovering more elaborated temperatures. Soil and vegetation components can replace aerodynamic temperature, which retrieval seems almost impossible. They can be inferred using multiangular measurements, via simple radiative transfer equations previously parameterized from simulation models. Retrieving sunlit and shaded components or canopy temperature profile requires inverting simulation models. Then, additional difficulties are the influence of thermal regime, and the limitations of spaceborne observations which have to be along track due to the temperature fluctuations. Finally, forefront investigations focus on adequately using TIR information with various spatial resolutions and temporal samplings, to monitor the considered processes with adequate spatial and temporal scales. [ABSTRACT FROM AUTHOR]
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- 2008
- Full Text
- View/download PDF
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