MULTI-SOURCE AND MULTI-SCALE SOIL MOISTURE DYNAMIC MODELLING IN MOUNTAIN MEADOWS

A comparison among multi-source data with the main aim to detect soil moisture dynamics in an Alpine catchment is presented. The data sources are: ground measurements derived from field campaigns and meteorological stations, simulations from a hydrological model and estimates derived from SAR images. The test site is located in the northwestern part of South Tyrol, mainly covered by pastures and meadows. The analysis indicates that the diverse sources are able to detect soil moisture dynamics at different spatial and temporal scales. Remote-sensing observations show consistent patterns through the summer season. Major control is land-use, with irrigated meadows in the bottom of the valley being the moister areas, and pastures along the upper hillslope the driest areas. Secondary control is topography, with increased moisture in convergent locations. Model simulations better reproduce the temporal trends as also detected by the ground stations; however, spatial patterns are quite different, with models results showing a much more uniform distribution.