On the synergic use of Sentinel-1 and CoreH2O SAR data for the retrieval of snow water equivalent on land and glaciers

The potential of multi-frequency multi-polarization SAR observation for the study of the Earth's bio- and geo-physical variables have been proven in the past by using airborne and shuttle-based SAR systems. However, in spite of its widely recognized potential, wavelength diversity remains out of reach of the research community due to the lack of space-borne data that operate at a single frequency on a given platform. In this context a possible improvement is expected by the Cold Regions Hydrology High-Resolution Observatory (CoReH2O) mission, selected for scientific and technical feasibility studies (Phase-A) within the Earth Explorer Programme of the European Space Agency, which combines a X- and Ku-band SAR operating on a single platform. Within the project the specific error sources for the combined use of Sentinel-1 and CoReH2O data are discussed. Unlike data acquired by a single satellite platform during one overpass, the combined use of data from two or more platforms is subject to additional error sources. In this case absolute errors of one sensor add up (sometimes compensate) as relative errors too each other. Three possible errors sources are identified and discussed : co-registration, geo-coding and radiometric calibration respectively