Remote Sensing of Snow Cover Using Spaceborne SAR: A Review

Abstract

The importance of snow cover extent (SCE) has been proven to strongly link with various \nnatural phenomenon and human activities; consequently, monitoring snow cover is one the most \ncritical topics in studying and understanding the cryosphere. As snow cover can vary significantly \nwithin short time spans and often extends over vast areas, spaceborne remote sensing constitutes \nan efficient observation technique to track it continuously. However, as optical imagery is limited \nby cloud cover and polar darkness, synthetic aperture radar (SAR) attracted more attention for its \nability to sense day-and-night under any cloud and weather condition. In addition to widely applied \nbackscattering-based method, thanks to the advancements of spaceborne SAR sensors and image \nprocessing techniques, many new approaches based on interferometric SAR (InSAR) and polarimetric \nSAR (PolSAR) have been developed since the launch of ERS-1 in 1991 to monitor snow cover under \nboth dry and wet snow conditions. Critical auxiliary data including DEM, land cover information, \nand local meteorological data have also been explored to aid the snow cover analysis. This review \npresents an overview of existing studies and discusses the advantages, constraints, and trajectories of \nthe current developments.