Refined incidence angle correction for operational soil moisture retrieval from ENVISAT ASAR WSM observations

Within this paper, the improvement of the incidence angle correction of ENVISAT ASAR WSM, based on the analyses of time series of observations in Southern Germany, are described. Based on operational ASAR processing, the soil moisture of the Upper Danube catchment was retrieved. During the analysis of the Wide Swath data, a remaining incidence angle effect, independent from terrain and land surface properties was observed. Based on the data of more than 400 WSM datasets, an empiric correction method was tested and applied to refine the soil moisture retrieval for the area. After this correction, the results of soil moisture comparisons between ASAR observations, SMOS retrieval and station measurements could be improved.