Utilization of Radarsat in integrated catchment management

This paper discusses the development and validation of an algorithm for extracting soil moisture data from Radarsat images in a form suitable for hydrological simulations and forecasts. A total of seven ascending Radarsat images of the Châteauguay River basin were acquired approximately at 18:00 h local time, between 2 May and 10 November 1998. Soil moisture information was extracted at the field level from Radarsat C-Band SAR using a semiempirical radar backscatter model. Soil surface roughness was evaluated at the basin scale using a test image and assuming known soil moisture conditions. Soil moisture maps were then produced at the basin scale. These maps are then extended to the root zone using correlation functions obtained from the Richards equation, thus producing basin-scale soil moisture maps suitable for hydrological modelling purposes.