The Potential of Scatterometer Derived Soil Moisture for Catchment Scale Modelling

Resumen

Radar remote sensing offers emerging capabilities to monitor global hydrological processes. Onlyrecently, the ERS scatterometer has been used successfully to derive soil moisture information with weeklyto decadal temporal resolution. Novel scatterometer systems like NASA’s SeaWinds and EUMETSAT’sAdvanced Scatterometer will provide a flow of operational coarse resolution data for monitoring meso-scalehydrological processes. Currently, concepts of how to integrate scatterometer products in hydrologic modelsare still vague. The coarse resolution of the data in the range of 10-50 km is often felt to impede hydrologicalapplications. However, by careful consideration of scaling properties of the soil moisture field the remotelysensed information may also be used on a catchment scale (>100 km²). In the paper two examples will bepresented which provide a first indication of the usefulness of scatterometer data at the catchment scale. Inthe first example scaling issues will be discussed based on a comparison with in-situ soil moisture data overthe Duero Basin in Spain. In a second example, it will be demonstrate that runoff can be estimated with aforecast range of several weeks by integrating low resolution soil moisture over sub basins of the Zambeziriver in Africa.