Microwave remote sensing of alpine snow

In the alpine zone snow is a dominant factor for more than half of the year and has strong influence on the ecosystem and economy. The knowledge of snow coverage, structure, liquid water content etc. is important and useful for many applications ranging from flood management to avalanche warning. Remote sensing from space has good potential to address these needs. Within ASSIST, Alpine Safety, Security and Information services and Technologies, these topics are also of interest. Two snow related products were identified that can be produced on an operational base with the available satellite systems to be ingested into the ASSIST service. Avalanche maps, mapping the contours of avalanches, and snow cover maps, mapping the snow covered area. The produced products are in good agreement with validation data. Unfortunately the current available satellite systems (mainly c-band SAR that is applicable) are not very well suited for snow related applications due to the small influence of the dry snow on the microwave signal at C- band. To overcome this limitation the CoReH2O mission was designed. With its X- and Ku-band system and repeat rates of 3 and 15 days it has high potential for alpine snow applications. Additional microwave signature measurements at these frequencies with standardized and reproducible snow characterization information will be needed for model development and validation. Recent developments allow a more quantitative snow characterizations and will be considered in the SnowScat project in combination with traditional snow characterization methods.