The potential of SAR in hydrology

Synthetic aperture radar (SAR) offers many possibilities for providing new data in process scale hydrology because of its response to variations in soil moisture and snow properties and its excellent spatial resolution. The achievable spatial resolution with SARs, on the order of a few tens of meters, is the same scale as the spatial distribution of soil moisture gradients caused by the variability in soil properties or terrain features found in the natural environment. It is also the same scale as the distribution of snow depth and water content, particularly in mountainous regions. To date the influence of other target features, specifically vegetation, roughness, and topography, has reduced the utility of applying SAR data successfully to hydrology. These problems are discussed with suggestions for minimizing these effects