Science Service System

Summary of Proposal MTH2359

TitleMonitoring Alpine Springtime Snow Melt with Wide Swath TSX
Investigator Small, David - University of Zurich, Dept. of Geography, Remote Sensing Laboratories
Team Members
Dr. Schubert, Adrian - University of Zurich, Dept. of Geography, Remote Sensing Laboratories
Dr. Jonas, Tobias - Swiss Institute for Snow and Avalanche Research, Snow hydrology
Dr. Ewen, Tracy - University of Zurich, Hydroloy and Climate - H2K - Dept. of Geography
Dr. Wiessman, Andreas - Gamma Remote Sensing, Applications
Dr. Small, David - University of Zurich, Dept. of Geography, Remote Sensing Laboratories
Dr. Bühler, Yves - WSL Institute for Snow and Avalanche Research SLF, Snow Avalanches and Prevention
SummaryExperience with archival ASAR WS imagery covering the Swiss Alps (2002-12) shows regular seasonal melt events from early March to mid-June each year. Experiences with Radarsat-2 SCNB images have shown wide-swath wet snow-cover signatures at higher spatial resolution. We propose here that a targeted short acquisition plan with high temporal density and ~3 months duration in the springtime would provide improved estimates of wet snow cover, pointing the way to possible future services based on Sentinel-1 and TerraSAR-X-based data streams. A new radiometric terrain correction methodology developed at the University of Zurich improves the comparability of backscatter estimates from multiple tracks. This removes the single-track exact repeat-pass constraint that is typically present when mapping wet snow in mountainous regions. We request a campaign of high temporal-density TSX Wide ScanSAR acquisitions over Switzerland. We propose biweekly revisits in 2014, followed by a mean revisit interval of less than 7 days in the 2015 melt period. In synergy with Sentinel-1 observations as well as optical (e.g. VIIRS) satellite data, evaluation of TSX snow wetness retrievals will be carried out. Combined analysis of optical and radar data has a high potential to derive complementary information quantifying snow cover area and its physical conditions, e.g. at the lower and upper elevation boundaries of snow cover. We believe that the time-series of TSX acquisitions over Switzerland proposed here would enable the testing of a new kind of “timely” SAR image product that could find direct application in snow hydrology models at both local and national levels. One team member will concentrate on on optical-based retrievals and analysis. Another will focus on validations at local catchment levels. Another will concentrate on issues associated with national-scale validation and integration into operational wet-snow mapping processing chains. The project would enable a test of integration of TSX SAR imagery into the Swiss national level wet snow mapping operations by WSL Institute for Snow and Avalanche Research SLF (WSL-SLF). The aim is to publish selected results from the investigations in scientific journal papers, with a final report summarising the project’s accomplishments. Internal funding sources are foreseen for the work by each partner.

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