Remote sensing of snow cover in mountainous regions

Abstract

Snow cover is an important variable for water availability, it influences the radiation budget of the Earth surface, and may cause natural disasters such as avalanches or floods after the melting process. Within Europe especially in Norway, Sweden, and Switzerland, snow is an important source of freshwater for reservoirs and the subsequent production of electricity. Climate change affects parameters such as snow cover duration (SCD), generally leading to its decrease, a delayed snow cover onset and earlier snow melt. Further effects also include fewer frost days, reduced snow depth, reduced snow water equivalent, changes in soil frost and snow-fed river systems. In order to quantify the effect of climate change on snow cover in mountainous regions worldwide, remote sensing data is a suitable source of information. Medium resolution remote sensing data originating from Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS), and Sentinel-3 as well as high resolution data provided by Landsat and Sentinel-1/-2 are available since the 1980s, allowing for long-term time series analysis of snow cover developments. Cloud cover, data gaps, and the pronounced topography constitute some of the major challenges that typically occur within mountain regions. The presentation will give a short overview of some of the techniques used to detect snow cover relying on different remote sensing data, while also methods for overcoming the aforementioned challenges will be introduced. Finally, the effect of climate change on snow cover in mountain regions will be illustrated for two example regions: Central Asia and Europe.