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914 results on '"Kerr, Yann"'

153. Detection of Irrigated Crops from Sentinel-1 and Sentinel-2 Data to Estimate Seasonal Groundwater Use in South India

Author

Ferrant, Sylvain, Selles, Adrien, Le Page, Michel, Herrault, Pierre-Alexis, Pelletier, Charlotte, Al-Bitar, Ahmad, Mermoz, Stéphane, Gascoin, Simon, Bouvet, Alexandre, Saqalli, Mehdi, Dewandel, Benoît, Caballero, Yvan, Ahmed, Shakeel, Maréchal, Jean-Christophe, Kerr, Yann, 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), Université Pierre et Marie Curie - Paris 6 (UPMC), Géographie de l'environnement (GEODE), Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS), Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre [Ispra] (JRC), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Indo-French Centre for Groundwater Research (IFCGR), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-National Geophysical Research Institute [Hyderabad] (NGRI), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), 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 de la Recherche Scientifique (CNRS)-Université Toulouse - Jean Jaurès (UT2J), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-MINES ParisTech - École nationale supérieure des mines de Paris-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 Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Indo-French Center for Groundwater Research (IFCGR), Institut de Recherche pour le Développement ( IRD [Nouvelle-Calédonie] ), Université Pierre et Marie Curie - Paris 6 ( UPMC ), Centre d'études spatiales de la biosphère ( CESBIO ), Université Paul Sabatier - Toulouse 3 ( UPS ) -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 ), Géographie de l'environnement ( GEODE ), Centre National de la Recherche Scientifique ( CNRS ) -Université Toulouse - Jean Jaurès ( UT2J ), Institut d'Electronique et de Télécommunications de Rennes ( IETR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées - Rennes ( INSA Rennes ) -SUPELEC-Centre National de la Recherche Scientifique ( CNRS ), Structure et fonctionnement des systèmes hydriques continentaux ( SISYPHE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -École pratique des hautes études ( EPHE ) -MINES ParisTech - École nationale supérieure des mines de Paris-Centre National de la Recherche Scientifique ( CNRS ), JRC Institute for Environment and Sustainability ( IES ), European Commission - Joint Research Centre [Ispra] ( JRC ), Bureau de Recherches Géologiques et Minières (BRGM) ( BRGM ), and Indo-French Centre for Groundwater Research ( IFCGR )

Subjects
Science, agro-hydrology, groundwater shortage monitoring, [SDE.ES]Environmental Sciences/Environmental and Society, [ SDE ] Environmental Sciences, [SDE]Environmental Sciences, Sentinel-1, radar and optical synergy, Sentinel-2, crop cover mapping, [ SDE.ES ] Environmental Sciences/Environmental and Society, ComputingMilieux_MISCELLANEOUS, random forest, rice irrigation
Abstract

Indian agriculture relies on monsoon rainfall and irrigation from surface and groundwater. The interannual variability of monsoon rainfalls is high, which forces South Indian farmers to adapt their irrigated areas to local water availability. In this study, we have developed and tested a methodology for monitoring these spatiotemporal variations using Sentinel-1 and -2 observations over the Kudaliar catchment, Telangana State (~1000 km2). These free radar and optical data have been acquired since 2015 on a weekly basis over continental areas, at a high spatial resolution (10–20 m) that is well adapted to the small areas of South Indian field crops. A machine learning algorithm, the Random Forest method, was used over three growing seasons (January to March and July to November 2016 and January to March 2017) to classify small patches of inundated rice paddy, maize, and other irrigated crops, as well as surface water stored in the small reservoirs scattered across the landscape. The crop production comprises only irrigated crops (less than 20% of the areas) during the dry season (Rabi, December to March), to which rain-fed cotton is added to reach 60% of the areas during the monsoon season (Kharif, June to November). Sentinel-1 radar backscatter provides useful observations during the cloudy monsoon season. The lowest irrigated area totals were found during Rabi 2016 and Kharif 2016, accounting for 3.5 and 5% with moderate classification confusion. This confusion decreases with increasing areas of irrigated crops during Rabi 2017. During this season, 16% of rice and 6% of irrigated crops were detected after the exceptional rainfalls observed in September. Surface water in small surface reservoirs reached 3% of the total area, which corresponds to a high value. The use of both Sentinel datasets improves the method accuracy and strengthens our confidence in the resulting maps. This methodology shows the potential of automatically monitoring, in near real time, the high short term variability of irrigated area totals in South India, as a proxy for estimating irrigated water and groundwater needs. These are estimated over the study period to range from 49.5 ± 0.78 mm (1.5% uncertainty) in Rabi 2016, and 44.9 ± 2.9 mm (6.5% uncertainty) in the Kharif season, to 226.2 ± 5.8 mm (2.5% uncertainty) in Rabi 2017. This variation must be related to groundwater recharge estimates that range from 10 mm to 160 mm·yr−1 in the Hyderabad region. These dynamic agro-hydrological variables estimated from Sentinel remote sensing data are crucial in calibrating runoff, aquifer recharge, water use and evapotranspiration for the spatially distributed agro-hydrological models employed to quantify the impacts of agriculture on water resources.

Published
2017

154. Comments on 'interference from 24-GHz automotive radars to passive microwave earth remote sensing satellites'

Author

Kerr, Yann H., Rochard, Guy, Tristant, Phillippe, English, Steve, Dreis, Markus, Stoffelen, Ad, Pla, Jean, Rommen, Bjorn, Marelli, Edoardo, Ruf, Klaus, and Bauer, Peter

Subjects
Artificial satellites in geographical research -- Research, Radar systems -- Research, Motor vehicles -- Equipment and supplies, Motor vehicles -- Research, Business, Earth sciences, Electronics and electrical industries
Abstract

In a recent paper, Younis et al. propose an apparently interesting methodology for the computation of the interference received by a spaceborne passive sensor from terrestrial interferences. However, the paper seems to require some clarifications, as some of the conclusions art' questionable. This comments paper aims at identifying the most outstanding issues of the publication. Index Terms--Automotive radar, compatibility, Earth Exploration Satellite Sensors (EESS), radiometry.

Published
2005

155. Wireless network of stand-alone end effect probes for soil in situ permittivity measurements over the 100MHZ-6GHz frequency range

Author

Demontoux, François, Bircher, Simone, Ruffié, Gilles, Bonnaudin, Fabrice, Wigneron, Jean Pierre, Kerr, Yann, Laboratoire de l'intégration, du matériau au système (IMS), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université Sciences et Technologies - Bordeaux 1, Université de Bordeaux (UB), 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), Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-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 Interactions Sol Plante Atmosphère (ISPA)

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SDE.IE]Environmental Sciences/Environmental Engineering, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

156. Efficiency of end effect probes for in-situ permittivity measurements in the 0.5 - 6 GHz frequency range and their application for organic soil horizons study

Author

Demontoux, François, Razafindratsima, Stephen, Bircher, Simone, Ruffié, Gilles, Bonnaudin, Fabrice, Jonard, François, Wigneron, Jean Pierre, Kerr, Yann H., Laboratoire de l'intégration, du matériau au système (IMS), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université Sciences et Technologies - Bordeaux 1, and Université de Bordeaux (UB)

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SDE.IE]Environmental Sciences/Environmental Engineering, [SDE.MCG]Environmental Sciences/Global Changes, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2017

157. Operational high resolution soil moisture for agricultural applications

Author

Escorihuela, Maria-José, Piou, Cyril, Merlin, Olivier, Abdallahi Ould Babah, Mohamed, Ghaout, Saïd, Diakite, Fakaba, Moumene, K., Cressman, Keith, Gao, Q., Amazirh, A., Er-raki, S., Fontanet, M., Ferrer, M., Cissé, Sory, Salem Benahi, Ahmed, Chirhane, J., Lazar, Mohamed, and Kerr, Yann

Subjects
P33 - Chimie et physique du sol, U30 - Méthodes de recherche, F06 - Irrigation, H10 - Ravageurs des plantes
Abstract

The purpose of this talk is to present the status and results from two projects that aim to use high resolution soil moisture operationally for agricultural applications. The first one (SMELLS) aims to improve current desert locust early warning systems by introducing high resolution soil moisture (1km) based on SMOS disaggregated soil moisture. Plagues of desert locusts, Schistocerca gregaria, have threatened agricultural production in Africa, the Middle East, and Asia for centuries. The livelihood of at least one-tenth of the world's human population can be affected by swarms of this insect. Currently, desert locust center use precipitation and NDVI index to forecast the areas with highest potential of desert locust breeding. To be able to take earlier the decision to send survey teams, one solution is to have timely information about soil moisture, which precedes vegetation. Our results show that soil moisture correlates well with desert locust presence and can explain current situation in Mauritania. The other project (REC) proposes a solution to the need of root-zone soil moisture at the crop scale for irrigation management. REC is based on an innovative operational algorithm that will allow for the first time to: 1) to map root zone soil moisture on a daily basis at the field scale and 2) to quantitatively evaluate the different components of the water budget at the field scale from readily available remote sensing data. The methodology relies on the coupling between a surface model representing the water fluxes at the land surface-atmosphere interface (infiltration, evaporation, transpiration) and in the soil (drainage), and remote sensing data composed of land surface temperature, and near-surface soil moisture retrieved from microwave radiometers and radars. These estimates will be integrated in an irrigation management system that will be used to trigger irrigation. Texte intégral)

Published
2017

158. SMOS-IC: an alternative SMOS soil moisture and 3 vegetation optical depth product

Author

Fernandez-Moran, Roberto, Al-Yaari, Amen, Mialon, Arnaud, Mahmoodi, Ali, Al Bitar, Ahmad, De Lannoy, Gabrielle, López-Baeza, Ernesto, Kerr, Yann, and Wigneron, Jean-Pierre

Subjects
SMOS, L-band, Level 3, ECMWF, SMOS-IC, soil moisture, vegetation optical depth, MODIS, NDVI
Abstract

The main goal of the Soil Moisture and Ocean Salinity (SMOS) mission over land surfaces is the production of global maps of soil moisture (SM) and vegetation optical depth (τ) based on multi-angular brightness temperature (TB) measurements at L-band. The operational SMOS Level 2 and Level 3 soil moisture algorithms account for different surface effects, such as vegetation opacity and soil roughness at 4 km resolution, in order to produce global retrievals of SM and τ. In this study, we present an alternative SMOS product which was developed by INRA (Institut National de la Recherche Agronomique) and CESBIO (Centre d’Etudes Spatiales de la BIOsphère). This SMOS-INRA-CESBIO (SMOS-IC) product provides daily SM and τ at the global scale and differs from the operational SMOS Level 3 (SMOSL3) product in the treatment of retrievals over heterogeneous pixels. Specifically, SMOS-IC is much simpler and does not account for corrections associated to the antenna pattern and the complex SMOS viewing angle geometry. It considers pixels as homogeneous to avoid uncertainties and errors linked to inconsistent auxiliary data sets which are used to characterize the pixel heterogeneity in the SMOS L3 algorithm. SMOS-IC also differs from the current SMOSL3 product (Version 300, V300) in the values of the effective vegetation scattering albedo (ω) and soil roughness parameters. An inter-comparison is presented in this study based on the use of ECMWF (European Center for Medium range Weather Forecasting) SM outputs and NDVI (Normalized Difference Vegetation Index) from MODIS (Moderate-Resolution Imaging Spectroradiometer). A 6 year (2010-2015) inter-comparison of the SMOS products SMOS-IC and SMOSL3 SM (V300) with ECMWF SM yielded higher correlations and lower ubRMSD (unbiased root mean square difference) for SMOS-IC over most of the pixels. In terms of τ, SMOS-IC τ was found to be better correlated to MODIS NDVI in most regions of the globe, with the exception of the Amazonian basin and of the northern mid-latitudes.

Published
2017

160. Agro-hydrology from Space

Author

Ferrant, Sylvain, Kerr, Yann, Selles, Adrien, Stephane Mermoz, Bouvet, Alexandre, Page, Michel Le, Al-Bitar, Ahmad, Mehrez Zribi, Gascoin, Simon, Jean-Christophe Maréchal, and Durand, Patrick

Published
2017
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161. SIMULEAU : Quantification des services naturels de régulation de la qualité des eaux dans un bassin versant du Sud : vers une plateforme intégrée pour la ressource en eau dans un contexte de changements environnementaux

Author

Sauvage, S., José Miguel Sánchez-Pérez, Jean-Luc Probst, Gerino, M., M Martinez, J., Gosset, M., Ribolzi Olivier, Alain Laraque, Fabien Guérin, Al Bitar Ahmad, Kerr, Yann H., Parens, M., Hélène Roux, Ricci, S., Calmant, S., Paris, A., Jean-Francois Cretaux, Dominique Laffly, Roland Seferian, Delire, C., Dominique Serça, Orange, D., Gil Mahe, Valentin, C., Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Géosciences Environnement Toulouse (GET), 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), 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), Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), 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)-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'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Géographie de l'environnement (GEODE), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse - Jean Jaurès (UT2J), Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Événements Extrêmes (EvExt), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

162. Microwave Brightness Of Land Surfaces From Outer Space

Author

Kerr, Yann H and Njoku, Eni G

Subjects
Physical Sciences
Abstract

Mathematical model approximates microwave radiation emitted by land surfaces traveling to microwave radiometer in outer space. Applied to measurements made by Scanning Multichannel Microwave Radiometer (SMMR). Developed for interpretation of microwave imagery of Earth to obtain distributions of various chemical, physical, and biological characteristics across its surface. Intended primarily for use in mapping moisture content of soil and fraction of Earth covered by vegetation. Advanced Very-High-Resolution Radiometer (AVHRR), provides additional information on vegetative cover, thereby making possible retrieval of soil-moisture values from SMMR measurements. Possible to monitor changes of land surface during intervals of 5 to 10 years, providing significant data for mathematical models of evolution of climate.

Published
1991

163. On the use of passive microwaves at 37 GHz

Author

Kerr, Yann H and Njoku, Eni G

Subjects
Earth Resources And Remote Sensing
Abstract

Recently a number of studies have been presented on the use of the 37 GHz channels of the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus 7 satellite, and on the synergisms between the SNMMR and the AVHRR (Advanced Very High Resolution Radiometer). The approaches are interesting but raise a number of questions on the validity of the interpretation of the results. A study to analyze the Microwave Polarization Difference Temperature (MPDT) in terms of sensitivity to surface and atmospheric parameters is presented. For this a radiative transfer model is used so as to depict the shortcomings of this index. Another approach, using lower frequencies is described and compared to the 37 GHz MPDT.

Published
1991

165. List of Authors

Author

Baghdadi, Nicolas, Barbu, Alina L., Bernier, Monique, Boniface, Karen, Boulet, Gilles, Boussetta, Souhail, Calmant, Stéphane, Calvet, Jean-Christophe, Cretaux, Jean-François, Dedieu, Jean-Pierre, De Rosnay, Patricia, Duguay, Yannick, Dumont, Marie, Egido, Alejandro, Frappart, Frédéric, Frison, Pierre-Louis, Gascoin, Simon, Jarlan, Lionel, Kerr, Yann, Lagouarde, Jean-Pierre, Leroux, Delphine, Magagi, Ramata, Motte, Erwan, Mougin, Eric, Pellarin, Thierry, Ramillien, Guillaume, Remy, Frédérique, Roussel, Nicolas, Seoane, Lucía, Wigneron, Jean-Pierre, and Zribi, Mehrez

Published
2016
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167. An evaluation of SMOS L-band vegetation optical depth (L-VOD) data sets: high sensitivity of L-VOD to above-ground biomass in Africa

Author

Rodríguez-Fernández, Nemesio J., primary, Mialon, Arnaud, additional, Mermoz, Stephane, additional, Bouvet, Alexandre, additional, Richaume, Philippe, additional, Al Bitar, Ahmad, additional, Al-Yaari, Amen, additional, Brandt, Martin, additional, Kaminski, Thomas, additional, Le Toan, Thuy, additional, Kerr, Yann H., additional, and Wigneron, Jean-Pierre, additional

Published
2018
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174. Synergies Betwwen Smos and Sentinel-3

Author

Kerr, Yann, primary, Wigneron, Jean Pierre, additional, Molero-Rodenas, Beatriz, additional, Rodriguez-Fernandez, Nemesio, additional, Al Bitar, Ahmad, additional, Suere, Christophe, additional, and Mecklenburg, Susanne, additional

Published
2018
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175. Present and Future of L-Band Radiometry

Author

Kerr, Yann, primary, Rodriguez-Fernandez, Nemesio, additional, Entekhabi, Dara, additional, Bindlish, Rajat, additional, Lee, Tong, additional, Yueh, Simon, additional, Lagerloef, Gary, additional, Pierre Wigneron, Jean, additional, Boutin, Jacqueline, additional, Reut, Nicolas, additional, and Kaleschke, Lars, additional

Published
2018
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176. SMOS Data Assimilation for Numerical Weather Prediction

Author

de Rosnay, Patricia, primary, Rodriguez-Fernandez, Nemesio, additional, Munoz-Sabater, Joaquin, additional, Albergel, Clement, additional, Fairbairn, David, additional, Lawrence, Heather, additional, English, Stephen, additional, Drusch, Matthias, additional, and Kerr, Yann, additional

Published
2018
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181. A semiempirical model for interpreting microwave emission from semiarid land surfaces as seen from space

Author

Kerr, Yann H and Njoku, Eni G

Subjects
Geophysics
Abstract

A radiative-transfer model for simulating microwave brightness temperatures over land surfaces is described. The model takes into account sensor viewing conditions (spacecraft altitude, viewing angle, frequency, and polarization) and atmospheric parameters over a soil surface characterized by its moisture, roughness, and temperature and covered with a layer of vegetation characterized by its temperature, water content, single scattering albedo, structure, and percent coverage. In order to reduce the influence of atmospheric and surface temperature effects, the brightness temperatures are expressed as polarization ratios that depend primarily on the soil moisture and roughness, canopy water content, and percentage of cover. The sensitivity of the polarization ratio to these parameters is investigated. Simulation of the temporal evolution of the microwave signal over semiarid areas in the African Sahel is presented and compared to actual satellite data from the SMMR instrument on Nimbus-7.

Published
1990
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183. The high sensitivity of SMOS L-Band vegetation optical depth to biomass

Author

Rodríguez-Fernández, Nemesio J., primary, Mialon, Arnaud, additional, Mermoz, Stephane, additional, Bouvet, Alexandre, additional, Richaume, Philippe, additional, Al Bitar, Ahmad, additional, Al-Yaari, Amen, additional, Brandt, Martin, additional, Kaminski, Thomas, additional, Le Toan, Thuy, additional, Kerr, Yann H., additional, and Wigneron, Jean-Pierre, additional

Published
2018
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184. Supplementary material to "The high sensitivity of SMOS L-Band vegetation optical depth to biomass"

Author

Rodríguez-Fernández, Nemesio J., primary, Mialon, Arnaud, additional, Mermoz, Stephane, additional, Bouvet, Alexandre, additional, Richaume, Philippe, additional, Al Bitar, Ahmad, additional, Al-Yaari, Amen, additional, Brandt, Martin, additional, Kaminski, Thomas, additional, Le Toan, Thuy, additional, Kerr, Yann H., additional, and Wigneron, Jean-Pierre, additional

Published
2018
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189. Satellite-based soil moisture validation and field experiments; Skylab to SMAP

Author

Jackson, Thomas, Wigneron, Jean-Pierre, Kerr, Yann H., Cosh, Michael, Colliander, Andreas, Walker, Jeffrey, Bindlish, Rajat, USDA-ARS : Agricultural Research Service, 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), California Institute of Technology (CALTECH), and Monash University

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience; Soil moisture remote sensing has reached a level of maturity that is now limited primarily by technology and funding. This is a result of extensive research and development that began in earnest in the 1970s and by the late 1990s had provided the basis and direction needed to support two dedicated satellite missions; Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active passive (SMAP). Field experiments have played a critical role in the development and implementation of these missions, as well as exploiting other satellites of opportunity. They continue to be of value in the validation and improvement of the soil moisture algorithms and products. Each of these experiments has involved at least two of the following four methodologies; tower, aircraft, satellite, and ground-based observations. Each methodology provides complementary information that expands the temporal or spatial information of the alternatives. The evolution, selected highlights, and lessons learned from these campaigns will be reviewed. Plans for upcoming SMAP post-launch field experiments will be presented.

Published
2016

190. Extreme events monitoring from space

Author

Kerr, Yann, Al Bitar, Ahmad, Mahmoodi, Ali, Richaume, Philippe, Al Yaari, Amen, Wigneron, Jean-Pierre, 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), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), 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 Interactions Sol Plante Atmosphère (UMR ISPA)

Subjects
analyse de données, interprétation des résultats, [SDE.MCG]Environmental Sciences/Global Changes, data analysis, projet smos, donnée satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3), vegetation water content over land, and ocean salinity. These geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge at a global scale is of interest for climatic and weather researches, and in particular in improving model forecasts. The Soil Moisture and Ocean Salinity mission has now been collecting data for 6 years. The whole data set has just been reprocessed (Version 620 for levels 1 and 2 and version 3 for level 3 CATDS). After 6 years it seems important to start using data for having a look at anomalies and see how they can relate to large scale events The purpose of this communication is to present the mission results after more than six years in orbit in a climatic trend perspective, as through such a period anomalies can be detected. Thereby we benefit from consistent datasets provided through the latest reprocessing using most recent algorithm enhancements. Using the above mentioned products it is possible to follow large events such as the evolution of the droughts in North America, or water fraction evolution over the Amazonian basin. In this occasion we will focus on the analysis of SMOS and ancillary products anomalies to reveal two climatic trends, the temporal evolution of water storage over the Indian continent in relation to rainfall anomalies, and the global impact of El Nino types of events on the general water storage distribution. This presentation shows in detail the use of long term data sets of L-band microwave radiometry in two specific cases, namely droughts and water budget over a large basin. Several other analyses are under way currently. Obviously, vegetation water content, but also dielectric constant, are carrying a wealth of information and some interesting perspectives will be presented.

Published
2016

191. SOIL moisture data intercomparison

Author

Kerr, Yann H., Rodriguez‐Fernandez, Nemesio, Al Yaari, Amen, Parrens, Marie, Molero, Beatriz, Mahmoodi, Ali, Mialon, Arnaud, Richaume, Philippe, Bindlish, Rajat, Mecklenburg, Susanne, Wigneron, Jean-Pierre, 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), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), United States Department of Agriculture, ESRIN, 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), 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), Interactions Sol Plante Atmosphère (UMR ISPA), and ESA Centre for Earth Observation (ESRIN)

Subjects
[SDV]Life Sciences [q-bio], projet smos, donnée satellite
Abstract

The Soil Moisture and Ocean Salinity satellite (SMOS) was launched in November 2009 and started delivering data in January 2010. Subsequently, the satellite has been in operation for over 6 years while the retrieval algorithms from Level 1 to Level 2 underwent significant evolutions as knowledge improved. Other approaches for retrieval at Level 2 over land were also investigated while Level 3 and 4 were initiated. In this présentation these improvements are assessed by inter-comparisons of the current Level 2 (V620) against the previous version (V551) and new products either using neural networks or Level 3. In addition a global evaluation of different SMOS soil moisture (SM) products is performed comparing products with those of model simulations and other satellites (AMSR E/ AMSR2 and ASCAT). Finally, all products were evaluated against in situ measurements of soil moisture (SM). The study demonstrated that the V620 shows a significant improvement (including those at level1 improving level2)) with respect to the earlier version V551. Results also show that neural network based approaches can yield excellent results over areas where other products are poor. Finally, global comparison indicates that SMOS behaves very well when compared to other sensors/approaches and gives consistent results over all surfaces from very dry (African Sahel, Arizona), to wet (tropical rain forests). RFI (Radio Frequency Interference) is still an issue even though detection has been greatly improved while RFI sources in several areas of the world are significantly reduced. When compared to other satellite products, the analysis shows that SMOS achieves its expected goals and is globally consistent over different eco climate regions from low to high latitudes and throughout the seasons.

Published
2016

192. Evaluation of three different data fusion approaches that uses satellite soil moisture from different passive microwave sensors to construct one consistent climate record

Author

Van der Schalie, Robin, De Jeu, Richard, Kerr, Yann, Wigneron, Jean-Pierre, Rodríguez-Fernández, Nemesio, Al Yaari, Amen, Drusch, Matthias, Mecklenburg, Susanne, Dolman, Han, Faculty of Earth and Life Sciences, VU University, Space Technology Center, 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), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), VU University Amsterdam, 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), Interactions Sol Plante Atmosphère (UMR ISPA), and Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU)

Subjects
analyse de données, remote sensing, capteur smos, télédétection, data analysis, capteur satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, soil moisture and ocean salinity
Abstract

Evaluation of three different data fusion approaches that uses satellite soil moisture from different passive microwave sensors to construct one consistent climate record. European Geosciences Union General Assembly 2016

Published
2016

193. SMOS and hydrology

Author

Kerr, Yann, Bircher, Simone, Rodriguez-Fernandez, Nemesio, Molero, Beatriz, Parrens, Marie, Leroux, Delphine, Pellarin, Thierry, Wigneron, Jean-Pierre, Mecklenburg, Susanne, 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), PhyREV - Processus Hydrologiques pour les Ressources en Eau Vulnérables, Laboratoire d’étude des Transferts en Hydrologie et Environnement (LTHE), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), ESRIN, 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), 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), Interactions Sol Plante Atmosphère (UMR ISPA), and ESA Centre for Earth Observation (ESRIN)

Subjects
remote sensing, bilan hydrologique, télédétection, [SDE.MCG]Environmental Sciences/Global Changes, projet smos, acquisition de données, water budget, radiometer, radiomètre, donnée satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

SMOS, a L Band radiometer using aperture synthesis to achieve a good spatial resolution, was successfully launched on November 2, 2009. It was developed and made under the leadership of the European Space Agency (ESA) as an Earth Explorer Opportunity mission. It is a joint program with the Centre National d’Etudes Spatiales (CNES) in France and the Centro para el Desarrollo Teccnologico Industrial (CDTI) in Spain. SMOS carries a single payload, an L band 2D interferometric, radiometer in the 1400-1427 MHz protected band. This wavelength penetrates well through the vegetation and the atmosphere is almost transparent enabling to infer both soil moisture and vegetation water content. SMOS achieves an unprecedented spatial resolution of 50 km at L-band maximum (43 km on average) with multi angular-dual polarized (or fully polarized) brightness temperatures over the globe and with a revisit time smaller than 3 days. SMOS has been now acquiring data for 5.5 years. The data quality exceeds what was expected, showing very good sensitivity and stability. The data is unfortunately impaired by man-made emission in the protected band, leading to degraded measurements in several areas including parts of Europe and of China. However, many different international teams are now addressing data use in various fields including hydrology. We have now acquired data over a number of significant “extreme events” such as droughts and floods giving useful information of potential applications. We are now working on the coupling with other models and or disaggregation to address soil moisture distribution over watersheds. We are also concentrating efforts on water budget and regional impacts. Assimilation of SMOS data into hydrological modelling showed positive impact in terms of stream flow and soil moisture estimation.With the development of a near real time soil moisture product using neural network approach, a wealth of new applications is bound to occur. From all those studies, it is now possible to express the “lessons learned” and derive a possible way forward. This paper thus gives an overview of the water cycle science goals of the SMOS mission, a description of its main elements, and a taste of the first results including performances at brightness temperature as well as at geophysical parameters level and how they are being put in good use for hydrological applications.

Published
2016

194. First application of regression analysis to retrieve soil moisture from SMAP brightness temperature observations consistent with SMOS soil moisture

Author

Al Yaari, Amen, Wigneron, Jean-Pierre, Kerr, Yann, Rodriguez-Fernandez, Nemesio, O'Neill, Peggy, Jackson, Thomas, De Lannoy, Gabrielle, Al Bitar, Ahmad, Mialon, Arnaud, Richaume, Philippe, Yueh, Simon, Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Department of Earth and Environmental Sciences [Leuven] (EES), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), United States Department of Agriculture, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, and Interactions Sol Plante Atmosphère (ISPA)

Subjects
remote sensing, télédétection, modèle de transfert radiatif, projet smos, équation de régression, donnée satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

Two dedicated soil moisture (SM) spaceborne missions, ESA’s Soil Moisture and Ocean Salinity (SMOS) and NASA’s Soil Moisture Active Passive (SMAP) satellites, were launched in 2009 and 2015, respectively. Both satellites have been providing microwave brightness temperature (TB) observations and SM retrievals at L-band since then (Entekhabi et al., 2010; Kerr et al., 2012). A recent study demonstrated the efficiency of physically-based multiple-linear regression equations (Wigneron et al., 2004) to retrieve SM from AMSR-E TB observations. The regression equations were derived analytically from the radiative transfer model. The purpose of that initial study was to extend the SMOS SM product into the past i.e., 2003-2009, using AMSR-E TB observations. The current study follows the same strategy to retrieve SM from SMAP TB observations with a purpose to extend the SMOS SM product into the future at the global scale. Regression coefficients were calibrated using SMOS horizontal and vertical TB observations and SM level 3 (SMOSL3 as a training data), over the 2013 - 2014 period. Based on these calibrated coefficients, global SM maps were produced from the SMAP TB observations during the 31/03-08/09/2015 period (referred here to as SMAP-reg). The SM data set obtained from SMAP TBs using the regression equations has been compared to the SMAP SM dataset computed withthe single channel algorithm and both exhibit the same temporal dynamics. For instance, figure 1 shows the (Pearson) correlation coefficient (R) between SMAP-reg and SMAP original SM over 31/03-08/09/2015. A remarkable agreement, R (mostly > 0.8), was obtained between the SMAP-reg and SMAP original SM products.Ongoing evaluations of the SMAP-reg SM product, with comparison to the SMAP original SM, against the global MERRA-Land SM simulations and in situ measurements will be presented. The main interest in the SMAP-reg SM product is that it is fully consistent with the SMOS Level 3 SM product. One of the key remaining tasks is toensure the consistent relative calibration between SMOS and SMAP TBs.

Published
2016

195. SMOS mission after 6 years in space: where are we?

Author

Kerr, Yann, Mecklenburg, Susanne, Delwart, Steven, Boutin, Jacqueline, Ferrazzoli, Paolo, Font, Jordi, Mahmoodi, Ali, Reul, Nicolas, Richaume, Philippe, Mialon, Arnaud, Al Yaari, Amen, Bircher, Simone, Wigneron, Jean-Pierre, 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), ESA Centre for Earth Observation (ESRIN), European Space Agency (ESA), Interactions et Processus au sein de la couche de Surface Océanique (IPSO), 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)-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)), 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), Università degli Studi di Roma Tor Vergata [Roma], Department of Physical and Technological Oceanography, Institut de Ciències del Mar, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), 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), ESRIN, 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 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), Interactions Sol Plante Atmosphère (ISPA), 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), 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)-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)), Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)

Subjects
remote sensing, télédétection, projet smos, diffusion des résultats, capteur satellite, température de brillance, donnée satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3) vegetation water content over land and ocean salinity. These geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge at a global scale is of interest for climatic and weather researches in particular in improving models forecasts. The SMOS instrument measures the passive microwave emission of the Earth surface at a frequency of 1,4 GHz (L-band). The instrument is an interferometer and provides brightness temperatures with an average resolution of 40 km, at several angles and dual polarizations. Data are acquired at two times in a day at 6 am and 18 pm (local time) and insure a complete coverage of the Earth surface in 3 days with a sampling of 15 km. The main products of the mission are of course Soil Moisture and Sea Surface salinity, but also vegetation opacity (directly related to water content) of vegetation covers including forests, surface dielectric constant for level two but also brightness temperatures at the surface, strong winds, root zone soil moisture and RFI (radio frequency interferences) maps. From Level 2 SMOS data several groups have started making new products several of them being either operational or on the verge of being such. We will show some of them or refer to related presentations. They include freeze defreeze (FMI), thin sea ice (Klimat Center Hamburg), near real time brightness temperatures and soon soil moisture (ECMWF), root zone soil moisture and drought indices (USDA and CESBIO). We are also working on more elaborate products such as water fractions, flood risk indices, improved precipitation with use of assimilated SMOS data, etc. The focus in this presentation will be given to the latter new science products. The purpose of this communication is to present the mission results after almost 6 years in orbit and a major re-processing as well as some outstanding results already obtained. A special attention will be devoted to level 2 products and to the retrieval quality improvements from version 3 (at launch) to the current version 620.

Published
2016

196. Global surface effects estimated by the L-band SMOS satellite

Author

Parrens, Marie, Mialon, Arnaud, Wigneron, Jean-Pierre, FERNANDEZ MORAN, Roberto, Richaume, Philippe, Ahmad, Al Bitar, Kerr, Yann H., 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), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), 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 Interactions Sol Plante Atmosphère (UMR ISPA)

Subjects
analyse de données, remote sensing, capteur smos, télédétection, [SDE.MCG]Environmental Sciences/Global Changes, data analysis, donnée satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, soil moisture and ocean salinity, rugosité du sol
Abstract

The Soil Moisture and Ocean Salinity (SMOS) mission is the first satellite dedicated to providing global surface soil moisture (SM). SMOS operates at L-band (1.4 GHz) and at this frequency, the signal depends on soil moisture and vegetation optical depth but it is also significantly affected by surface effects and in particular by the soil roughness. However, when dense vegetation is present, the L-band signal is poorly sensitive to the soil effects. First, by using multiple regressions between soil moisture (SM) and brightness temperature (TB) at different incidence angles and polarizations, SMOS sensitivity to the soil effects are evaluated. A global-scale map of SMOS sensitivity to the soil effects is computed and shows that for 87\% of the land surfaces, the SMOS observations are sensitive to the soil effects, while a very low sensitivity to the soil effects was estimated over ~ 13% of the land surfaces. For instance, over broadleaf evergreen forest (essentially the Amazon and Congo forest), SMOS is sensitive to the soil effects for only half of the pixels considered. In a second step, in L-MEB (L-band Microwave Emission of the Biosphere), the forward emission model of the SMOS algorithm , the vegetation and roughness effects were combined in only one parameter referred to as TR in this study. By inverting L-MEB, SM and TR were retrieved at global scale from the SMOS Level 3 (L3) TB observations during 2011. Assuming a linear relationship between TR and LAI obtained by the MODIS data, the effects of roughness and vegetation were decoupled and a global map of soil roughness effects (Hr) was estimated. It was found that the spatial pattern of the Hr values can be associated to the main vegetation types. Higher values of roughness (Hr=0.37-0.41) were obtained for forests (broadleaf evergreen, deciduous and mixed coniferous) while the lower values (Hr=0.15-0.17) were obtained for deserts, shrubs and bare soil. Intermediate values (Hr=0.15-0.20) were obtained over grasslands, tundra and cultivations Over vegetation biomes composed by forests and wooded grasslands, Hr values are mainly correlated to the vegetation density (R ~ 0.55). For deserts, shrubs and bare soil, the Hr values were mainly correlated to the topography slopes (R ~ 0.53). The global maps presented in this study, could lead to improved retrievals of soil moisture and vegetation optical depth for present, such as SMOS and the Soil Moisture Active Passive (SMAP), and future microwave remote sensing missions .

Published
2016

197. SMOS level 3 soil moisture database

Author

Mialon, Arnaud, Ahmad, Al Bitar, Cabot, François, Tarot, Stéphane, Pellarin, Thierry, Richaume, Philippe, Vandermarcq, Olivier, Wigneron, Jean-Pierre, Kerr, Yann H., 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), SISMER - Service des Systèmes d'Informations Scientifiques pour la MER, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d’étude des Transferts en Hydrologie et Environnement (LTHE), Centre National d'Études Spatiales [Toulouse] (CNES), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), 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 Interactions Sol Plante Atmosphère (UMR ISPA)

Subjects
[INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], projet smos, acquisition de données, température de brillance
Abstract

SMOS has been delivering data since January 2010. Three ground segments have been developed among which the CATDS (Centre Aval de Traitements des Données SMOS) by the French space agency CNES [2]. This ground segment is providing the users with level 3 data that are a bit different from ESA level 1 and level 2 as these products : i) are temporally aggregated as daily, during 3-day and 10-day time window and monthly averages ii) are projected on the EASE Grid version 2 iii) using the netcdf format iv) are derived using a modified algorithm taking advantage of 3 consecutive SMOS overpasses [4] v) brightness temperatures are averaged by bin of incidence angles in the Earth reference frame, i.e. H and V polarizations. Since the beginning of the mission the algorithm to derive the SMOS data has evolved due to improvements of the models and also due to better quality SMOS brightness temperatures. A reprocessing campaign has been done in fall 2015 to deliver the entire time series (2010-spring 2015) using the latest versions of the processors and with a more accurate brightness temperatures (improved bias reconstruction). The data are available on line (http://www.catds.fr/sipad/startPage.do) through the SIPAD (Système d’Information, de Préservation et d’Accès aux Données) which is a user-friendly dissemination service that allows the users to download their own products according to their criteria (as area of interest, period of time, subset of fields...). The aim of this communication is then to present the last updates and version of the products delivered by the CATDS that is the Version 3. Derived soil moisture values are validated by comparing to SMOS level 2 and in situ measurements acquired at various climate conditions.

Published
2016

198. Adaptation of the SMOS soil moisture retrieval algorithm for organic-rich soils and its validation over various Northern sites

Author

Bircher, Simone, Richaume, Philippe, Mahmoodi, Ali, Demontoux, François, Ikonen, Jaakko, Rautiainen, Kimmo, Vehviläinen, Juho, Moreaux, Virginie, Kim, Yongwon, Lee, Bang-Yong, Suzuki, Rikie, Ikawa, Hiroki, Oechel, Walter, Belelli Marchesini, Luca, Dolman, Han, Berg, Aaron, Jonard, François, Weihermüller, Lutz, Andreasen, Mie, Schwank, Mike, Wigneron, Jean-Pierre, Kerr, Yann H., 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 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), Finnish Meteorological Institute (FMI), Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), International Arctic Research Center (IARC), University of Alaska [Fairbanks] (UAF), Arctic Research Centre of Finnish Meteorological Institute, Korea Polar Research Institute (KOPRI), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Agro-Meteorology Division, National Institute of Agro-Environmental Sciences (NIAES), Global Change Research Group, South African National Biodiversity Institute, VU University Amsterdam, University of Guelph, Institute of Bio- and Geosciences Agrosphere (IBG-3), Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Swiss Federal Institute for Forest Snow and Landscape Research (WSL), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), 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), Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Interactions Sol Plante Atmosphère (UMR ISPA), and Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université Sciences et Technologies - Bordeaux 1

Subjects
remote sensing, sol organique, permittivité diélectrique, télédétection, modèle de transfert radiatif, [SDE.MCG]Environmental Sciences/Global Changes, projet smos, radiometer, radiomètre, permittivity, donnée satellite, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, humidité de surface
Abstract

From the passive L-band microwave radiometer onboard the Soil Moisture and Ocean Salinity (SMOS) space mission global surface soil moisture data is retrieved every 3 days. Thus far, the empirical L-band Microwave Emission of the Biosphere (L-MEB) radiative transfer model applied in the SMOS soil moisture retrieval algorithm is exclusively calibrated over test sites in dry and temperate climate zones and the included dielectric mixing model relating soil moisture to permittivity accounts only for mineral soils. However, soil moisture monitoring over the higher northern latitudes is crucial since these regions are especially sensitive to climate change and a considerable feedback is expected due to carbon liberated from thawing ground of these extremely organic soils. Due to differing structural characteristics and thus varying bound water fractions, the permittivity of organic material is lower than the one of most mineral soils at a given water content. This assumption was verified by means of measurements in organic and mineral substrates from various sites in Denmark, Finland, Scotland and Siberia. For this purpose, conventional soil moisture sensors were used as well as weak perturbation and waveguide techniques in order to infer effective soil permittivity at the microwave L-band (1-2 GHz). Based on these data, a generic L-band soil moisture – permittivity relation for organic soils was derived and validated with dielectric mixing model runs as well as literature data. Furthermore, the derived function was tested in the L-MEB model. Results showed that modeled data agreed with measurements from a tower-based passive L-band microwave radiometer observing organic-rich soil over a 2 months period in a highly controlled set-up. The generic «organic» empirical model was then implemented in the SMOS Prototype Algorithm to retrieve soil moisture over a site in Northern Finland. The validation with in situ soil moisture observations calibrated for organic soils showed a distinct improvement in the agreement between the satellite and ground datasets when using the «organic» instead of the operational SMOS processor version. This analysis is to be continued in more detail and the validation effort needs to be expanded over as many regions with abundant soil organic matter content as possible. Appropriate in situ observations are currently available from various sites in Alaska, Canada, and the Netherlands. In this communication, first the derivation of the generic L-band «organic» soil moisture-permittivity model will be presented. Focus will then be on the comparison of «organic» SMOS soil moisture retrievals with corresponding operational SMOS products as well as in situ observations over all available sites.

Published
2016

199. Soil moisture in French alpine valley using L-Band radiometer

Author

Mialon, Arnaud, Pellarin, Thierry, Lemaître, François, Richaume, Philippe, Wigneron, Jean-Pierre, Cabot, François, Kerr, Yann H., 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), ONERA - The French Aerospace Lab [Palaiseau], ONERA, Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), 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), ONERA-Université Paris Saclay (COmUE), Interactions Sol Plante Atmosphère (UMR ISPA), Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-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), ONERA - The French Aerospace Lab [Toulouse], and European Space Agency (ESA). INT.

Subjects
remote sensing, sonde de mesure, sensor, [SDV]Life Sciences [q-bio], télédétection, [SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences, diffusion des résultats, température de brillance, radiometer, radiomètre, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience; Since the launch of the satellite, a constant activity has been to compare SMOS derived soil moisture to in situ measurements to validate and improve the soil moisture retrieval. Many sites have been equipped with soil moisture probes and a few of them with L-Band radiometer placed on structures of ~10 m. height. The observed surfaces are homogeneous, i.e. one type of vegetation cover, whereas SMOS (~40km of resolution) observes more heterogeneous scenes, i.e. mix of different landscapes. Keeping this issue in mind, a new experimental site is proposed with the main objective to observe complex scenes to test the SMOS soil moisture retrieval. The LEWIS radiometer (L-Band radiometer for Estimating Water in Soil) has been placed by a cliff in St Hilaire du Touvet (French Alps) since May 2014. Its position allows us to monitor a surface 800m down below in the valley du Grésivaudan which is flat, avoiding topographic effect. The instrument has a beam width of 13.6° which implies a field of view of several hundreds of meters, covering various landscapes (agricultural fields, forest, lake). The instrument is equipped with 2 motors so that it moves in two directions (azimuth and elevation) and monitors regularly several areas of interest. It can also be pointed towards the deep sky for calibration. In addition, soil moisture and temperatures probes are placed in different fields in the Valley and a pyrometer is installed with the radiometer to measure the skin temperature of the observed scene. The first data confirm the consistency of Lewis measurements. The deep sky presents brightness temperatures of TBH = 5.4K et TBV = 4.3K, which is similar to what was observed at the SMOSREX site. This new site is planed to last 4 years to insure long time observations (L-band brightness temperatures and surface soil moisture) of heterogeneous scenes. Further works will also imply sun glint effect, snow detection and effect of urban areas.

Published
2016

200. Rainfall estimation by inverting SMOS soil moisture estimates: A comparison of different methods over Australia

Author

Brocca, Luca, Pellarin, Thierry, Crow, Wade T., Ciabatta, Luca, Massari, Christian, Ryu, Dongryeol, Su, Chun Hsu, Rüdiger, Christoph, and Kerr, Yann

Subjects
remote sensing, rainfall, soil moisture, SMOS
Abstract

Remote sensing of soil moisture has reached a level of maturity and accuracy for which the retrieved products can be used to improve hydrological and meteorological applications. In this study, the soil moisture product from the Soil Moisture and Ocean Salinity (SMOS) satellite is used for improving satellite rainfall estimates obtained from the Tropical Rainfall Measuring Mission multisatellite precipitation analysis product (TMPA) using three different "bottom up" techniques: SM2RAIN, Soil Moisture Analysis Rainfall Tool, and Antecedent Precipitation Index Modification. The implementation of these techniques aims at improving the well-known "top down" rainfall estimate derived from TMPA products (version 7) available in near real time. Ground observations provided by the Australian Water Availability Project are considered as a separate validation data set. The three algorithms are calibrated against the gauge-corrected TMPA reanalysis product, 3B42, and used for adjusting the TMPA real-time product, 3B42RT, using SMOS soil moisture data. The study area covers the entire Australian continent, and the analysis period ranges from January 2010 to November 2013. Results show that all the SMOS-based rainfall products improve the performance of 3B42RT, even at daily time scale (differently from previous investigations). The major improvements are obtained in terms of estimation of accumulated rainfall with a reduction of the root-mean-square error of more than 25%. Also, in terms of temporal dynamic (correlation) and rainfall detection (categorical scores) the SMOS-based products provide slightly better results with respect to 3B42RT, even though the relative performance between the methods is not always the same. The strengths and weaknesses of each algorithm and the spatial variability of their performances are identified in order to indicate the ways forward for this promising research activity. Results show that the integration of bottom up and top down approaches has the potential to improve the quality of near-real-time rainfall estimates from remote sensing in the near future.

Published
2016

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