Soil moisture measurement and retrieval using simulated ASAR imagery - Results of the Thames 1997 experiment

This paper reports results of research into the potential of ESA's future Advanced Synthetic Aperture Radar (ASAR) for soil moisture measurement and retrieval. Results from earlier simulation work using ERS-1 imagery, confirmed the sensitivity of ASAR backscatter to soil moisture at different spatial resolutions. New research conducted during 1997 aimed to extend the simulation and investigate the sensitivity of ASAR backscatter to soil moisture at different spatial resolutions and incidence angles. ASAR's high (30m), medium (150m) and low (1000m) resolution imaging modes were spatially and radiometrically simulated using ERS-2 and RADARSAT data. Work has proceeded at three test sites and the results are reported here for the Thames site in the UK. A comprehensive set of satellite imagery and ground data at catchment scale was acquired for this site during the 1997 crop growing period. ASAR products were simulated from 10 ERS-2 and 6 Radarsat images and the backscatter measurements compared to soil moisture measured an the day of acquisition. The results demonstrate the effects of crop cover, spatial resolution and incidence angle on soil moisture sensitivity and retrieval at the catchment scale.