A method for soil moisture estimation in Western Africa based on ERS Scatterometer
Résumé
The analysis of feedback phenomena which occur between continental surfaces and the atmosphere is one of the keys to an improved understanding of African Monsoon dynamics. For this reason the monitoring of surface parameters, in particular soil moisture, is very important. The present paper presents a new methodology for the estimation of surface soil moisture over Western Africa, based on data provided by the European Remote sensing Wind SCatterometer (WSC) instrument, in which an empirical model is used to estimate volumetric soil moisture. This approach takes into account the effects of vegetation and soil roughness in the soil moisture estimation process. The proposed estimations have been validated using different methods, and a good degree of coherence has been observed between satellite estimations and ground truth measurements over the Banizambou site in Niger. Moisture and rainfall estimations for the same site are shown to be strongly correlated. Comparison with the multi-model analysis product provided by the Global Soil Wetness Project, Phase 2 (GSWP-2) indicates that their estimations are well correlated, although land surface models provide slightly overestimated levels of soil moisture.