Baup F., Mougin Eric, Hiernaux P., Lopes A., Rosnay de P., Chênerie I. (2007). Radar signatures of sahelian surfaces in mali using ENVISAT-ASAR data. Ieee Transactions on Geoscience and Remote Sensing, 45 (7 - Part 2), p. 2354-2363. ISSN 0196-2892.
Titre du document
Radar signatures of sahelian surfaces in mali using ENVISAT-ASAR data
Baup F., Mougin Eric, Hiernaux P., Lopes A., Rosnay de P., Chênerie I.
Ieee Transactions on Geoscience and Remote Sensing, 2007,
45 (7 - Part 2), p. 2354-2363 ISSN 0196-2892
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.