Merlin Olivier auteur aut IRD Al Bitar A. auteur aut IRD Walker J.P. auteur aut IRD Kerr Yann auteur aut IRD text journalArticle eng text/pdf born digital access A sequential model is developed to disaggregate microwave-derived soil moisture from 40 km to 4 km resolution using MODIS (Moderate Imaging Spectroradiometer) data and subsequently from 4 km to 500 m resolution using ASTER (Advanced Scanning Thermal Emission and Reflection Radiometer) data. The 1 km resolution airborne data collected during the three-week National Airborne Field Experiment 2006 (NAFE'06) are used to simulate the 40 km pixels, and a thermal-based disaggregation algorithm is applied using 1 km resolution MODIS and 100 m resolution ASTER data. The downscaled soil moisture data are subsequently evaluated using a combination of airborne and in situ soil moisture measurements. A key step in the procedure is to identify an optimal downscaling resolution in terms of disaggregation accuracy and sub-pixel soil moisture variability. Very consistent optimal downscaling resolutions are obtained for MODIS aboard Terra, MODIS aboard Aqua and ASTER, which are 4 to 5 times the thermal sensor resolution. The root mean square error between the 500 m resolution sequentially disaggregated and ground-measured soil moisture is 0.062 vol./vol. with a bias of -0.045 vol./vol. and values ranging from 0.08 to 0.40 vol./vol. specialized Disaggregation Soil moisture Fractal Scaling Multi-sensor NAFE SMOS MODIS ASTER 126 072 113 10 2275-2284 2009 0034-4257 https://www.documentation.ird.fr/hor/fdi:010048191 10.1016/j.rse.2009.06.012 0034-4257 [F B010048191] https://www.documentation.ird.fr/hor/fdi:010048191 https://www.documentation.ird.fr/intranet/publi/2009/09/010048191.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2009-10-07 2017-08-23 fdi:010048191 fre