The determination of hydrological model parameters from airborne interferometric SAR-data

By taking advantage of the phase information, SAR-interferometry provides the possibility of generating digital terrain models (DTM). This form of application has gained continuosly more recognition in the field of microwave remote sensing, since numerous scientific disciplines, such as hydrology demand high resoluting DTMs. For the purpose of driving physically based soil-vegetation-atmosphere-transfer models (SVAT) a large variety of model parameters have to be provided. Among these, the topographical parameters, such as altitude, terrain slope. Until now topographical model parameters are mainly derived from publically available digital terrain models, which suffer a lack of accuracy resulting from poor horizontal and vertical resolution. This study investigates the accuracy of airborne SAR-interferometric digital terrain models and its use within a hydrological framework. Therefore a large number of differential GPS-measurements were conducted in order to verify the SAR-data provided by the AeS-1, a single-pass sensor developed by Aero-Sensing Radarsysteme GmbH, Germany. The nominal ground resolution of the sensor is given with 1 m horizontally and up to 5 cm in vertical direction. In comparison to a regular, publically available DTM, the necessity and the possibilities of high-resoluting DTMs for hydrological modelling are shown