HR: 0800h
AN: H51C-02    [Abstracts]
TI: Large Scale Evaluation of AMSR-E Soil Moisture Products Based on Ground Soil Moisture Network Measurements
AU: Gruhier, C
EM: claire.gruhier@cesbio.cnes.fr
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: de Rosnay, P
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: Richaume, P
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: Kerr, Y
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: Rudiger, C
AF: Meteo-France, CNRM/GAME, URA CNRS 1357, Toulouse, 31000, France
AU: Boulet, G
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: * Walker, J P
EM: j.walker@unimelb.edu.au
AF: Dept Civil and Env Eng, University of Melbourne, Parkville, Australia
AU: Mougin, E
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: Mougin, E
AF: Institut de Recherche pour le Developpement (IRD), avenue de l'hippodrome, Bamako, Mali
AU: Ceschia, E
AF: Centre d'Etude Spatiale de la BIOsphere (CESBIO), bpi 2801 18 avenue Edouard Belin, Toulouse cedex 9, 31401, France
AU: Calvet, J
AF: Meteo-France, CNRM/GAME, URA CNRS 1357, Toulouse, 31000, France
AB: This paper presents an evaluation of AMSR-E (Advanced Microwave Scanning Radiometer for EOS) soil moisture products, based on a comparison with three ground soil moisture networks. The selected ground sites are representative of various climatic, hydrologic and environmental conditions in temperate and semi-arid areas. They are located in the south-west of France, south-east of Australia and the Gourma region of the Sahel. These sites were respectively implemented in the framework of the projects SMOSREX (Surface Monitoring Of Soil Reservoir Experiment), SASMAS/GoREx (Scaling and Assimilation of Soil Moisture and Streamflow in the Goulburn River Experimental catchment) and AMMA (African Monsoon Multidisciplinary Analysis). In all cases, the arrangement of the soil moisture measuring sites was specifically designed to address the validation of remotely sensed soil moisture in the context of the preparation of the SMOS (Soil Moisture and Ocean Salinity) project. For the purpose of this study, 25km AMSR-E products were used, including brightness temperatures at 6.9 and 10.7 GHz, and derived soil moisture. The study is focused on the year 2005. It is based on ground soil moisture network measurements from 4 stations for SMOSREX extended to the SUDOUEST project of CESBIO, 12 stations for GoRex, and 4 stations for AMMA. Temporal and spatial features of soil moisture variability and stability is a critical issue to be addressed for remotely sensed soil moisture validation. While ground measurements provide information on soil moisture dynamics at local scale and high temporal resolution (hourly), satellite measurements are sparser in time (up to several days), but cover a larger region (25km x 25km for AMSR-E). First, a statistical analysis, including mean relative difference and Spearman rank, is conducted for the three soil moisture networks. This method is mainly based on the approach proposed by Cosh et al. (2004) for the purpose of the use of ground networks for satellite remote sensing validation. It allows to capture soil moisture variability features and to identify for each site the most representative station. Second, a comparison of AMSR-E derived and in-situ soil moisture measurements was conducted. Volumetric soil moisture obtained from ground and satellite measurements are compared for both absolute and normalized values. For the three sites, results suggest that although AMSR-E soil moisture products are not able to capture the same range of soil moisture values as in-situ measurements, they provide reliable information on surface soil moisture temporal variability over the three sites. It is shown, however, that the use of radiometric products such as polarization ratio provide better agreement with ground stations, than the derived soil moisture products.
DE: 1848 Monitoring networks
DE: 1855 Remote sensing (1640)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2007 Joint Assembly