Soil moisture dynamics from Synthetic Aperture Radar for Hydrometeorological Applications in the Southern African Development Community

A soil moisture monitoring service for the region of the Southern African Development Community (SADC) has been developed within the ESA TIGER Innovator project SHARE (www.ipf.tuwien.ac.at/radar/share). This service addresses one of today's most severe obstacles in water resource management which is the lack of availability of reliable soil moisture information on a dynamic basis. The spatial resolution of the product is 1 km and data are available up to twice per week for southern Africa since December 2004. In this paper the assessment of the new extensive soil moisture dataset is presented. This includes the comparison with other remotely sensed products (precipitation) and ground measurements. River runoff measurements reflect the hydrological state of the upstream basin. Thus, the relationship of relative soil moisture and river runoff has been investigated. Correlations of >0.9 (R2) are found for subtropical basins with respect to a catchment specific temporal offset. If knowledge is established about this relationship and also the spatial patterns, flood risk assessments can be enhanced. Soil moisture deficits can be identified once a sufficiently long time series becomes available.