Baup F. auteur aut IRD Mougin Eric auteur aut IRD Hiernaux P. auteur aut IRD Lopes A. auteur aut IRD Rosnay de P. auteur aut IRD Chênerie I. auteur aut IRD text journalArticle eng This paper presents an analysis of ENSIVAT Advanced Synthetic Aperture Radar data acquired over a Sahelian region located in Mali, West Africa. The considered period is 2004-2005 and includes two rainy seasons. Emphasis is put on two ScanSAR modes, namely, the Global Monitoring (GM) and the Wide Swath (WS) modes characterized by spatial resolutions of about I km and 150 m, respectively. Results show that the WS mode offers better performance in terms of radiometric resolution, radiometric stability, and speckle reduction than the GM mode. The latter is more appropriate for studies at large scale (> 10 x 10 km). In both modes, pronounced angular and temporal signatures are observed for most soil surfaces, and azimuthal effects are observed on markedly orientated rocky surfaces. In contrast, polarization differences (VV/HH) are small during the dry season except on flat loamy soil surfaces. Finally, a relationship is observed between the normalized WS backscattering signal at HH polarization and the surface soil moisture of sandy soils. specialized Advanced Synthetic Aperture Radar ASAR ENVISAT global monitoring radar sahel soil moisture wide swath 126 068 45 7 - Part 2 2354-2363 2007 0196-2892 https://www.documentation.ird.fr/hor/PAR00001881 10.1109/TGRS.2007.893824 0196-2892 https://www.documentation.ird.fr/hor/PAR00001881 IRD - Base Horizon / Pleins textes 2007-11-06 2017-08-23 PAR00001881 fre