%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Merlin, O.
%A Rudiger, C.
%A Al Bitar, A.
%A Richaume, P.
%A Walker, J.P.
%A Kerr, Yann
%T Disaggregation of SMOS soil moisture in Southeastern Australia
%D 2012
%L PAR00008801
%G ENG
%J IEEE Transactions on Geoscience and Remote Sensing
%@ 0196-2892
%K Australian Airborne Calibration/validation Experiments for SMOS (AACES) ; calibration/validation ; disaggregation ; Disaggregation based on Physical ; And Theoretical scale Change (DisPATCh) ; field campaign ; Moderate ; Resolution Imaging Spectroradiometer (MODIS) ; Soil Moisture and Ocean ; Salinity (SMOS)
%M ISI:000303205200018
%N 5
%P 1556-1571
%R 10.1109/tgrs.2011.2175000
%U https://www.documentation.ird.fr/hor/PAR00008801
%V 50
%W Horizon (IRD)
%X Disaggregation based on Physical And Theoretical scale Change (DisPATCh) is an algorithm dedicated to the disaggregation of soil moisture observations using high-resolution soil temperature data. DisPATCh converts soil temperature fields into soil moisture fields given a semi-empirical soil evaporative efficiency model and a first-order Taylor series expansion around the field-mean soil moisture. In this study, the disaggregation approach is applied to Soil Moisture and Ocean Salinity (SMOS) satellite data over the 500 km by 100 km Australian Airborne Calibration/validation Experiments for SMOS (AACES) area. The 40-km resolution SMOS surface soil moisture pixels are disaggregated at 1-km resolution using the soil skin temperature derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data, and subsequently compared with the AACES intensive ground measurements aggregated at 1-km resolution. The objective is to test DisPATCh under various surface and atmospheric conditions. It is found that the accuracy of disaggregation products varies greatly according to season: while the correlation coefficient between disaggregated and in situ soil moisture is about 0.7 during the summer AACES, it is approximately zero during the winter AACES, consistent with a weaker coupling between evaporation and surface soil moisture in temperate than in semi-arid climate. Moreover, during the summer AACES, the correlation coefficient between disaggregated and in situ soil moisture is increased from 0.70 to 0.85, by separating the 1-km pixels where MODIS temperature is mainly controlled by soil evaporation, from those where MODIS temperature is controlled by both soil evaporation and vegetation transpiration. It is also found that the 5-km resolution atmospheric correction of the official MODIS temperature data has a significant impact on DisPATCh output. An alternative atmospheric correction at 40-km resolution increases the correlation coefficient between disaggregated and in situ soil moisture from 0.72 to 0.82 during the summer AACES. Results indicate that DisPATCh has a strong potential in low-vegetated semi-arid areas where it can be used as a tool to evaluate SMOS data (by reducing the mismatch in spatial extent between SMOS observations and localized in situ measurements), and as a further step, to derive a 1-km resolution soil moisture product adapted for large-scale hydrological studies.
%$ 072 ; 126