Snow monitoring
Contents
The snow cover is an integral and critical component of the Earth System in regard to climate. It is extremely sensitive to climate change and has significant feedback on the atmosphere. Changes in climate lead to changes in the extent, thickness, density, and optical and thermal properties of the snow cover, and hence of the Earth’s surface and the boundary layer between the Earth and the Atmosphere. These changes have far-reaching consequences on glaciers, extreme events, natural hazards, ecosystems, biodiversity, forests, and landscapes, as well as winter sports and the tourism industry, globally and in Switzerland. This includes impacts on water resources for irrigation, drinking water, and hydropower. Snow as frozen precipitation is globally of increasing importance in a world which is faced on the one hand by more frequent droughts and on the other hand by more extreme precipitation events, where snow can dampen immediate run-off but on the other hand also cause avalanches or floods. Decreasing snow cover extent due to both climate warming and increasing loads of dust and soot lowers the planetary albedo, which changes the energy balance of our planet.
The global monitoring of snow variables thus becomes increasingly important and requires the exchange of knowledge about measuring snow variables, with common best practices developed and applied broadly to allow comparability. One aim of snow monitoring is thus to obtain precise long term snow data sets and to make them readily usable in practice and for snow climatology studies.
Snow monitoring at SLF
SLF has established an outstanding reputation for excellence in snow climatology, in situ snow monitoring, and data curation. The research at SLF has contributed significantly to our understanding of snow in the climate system through the development of snow-climatological data products (anomaly maps), trend analyses (snow day index), numerical models (see snow-cover modelling), including data management and visualization tools. The institute has been engaged in those activities for decades.
Researchers at SLF have access to a high-quality measuring infrastructure, which, together with the constantly evolving measurement instruments and methods, has been continuously expanded for more than 80 years. A well-known example is the Weissfluhjoch test site (2536 m above sea level) where SLF has been recording snow data manually since 1936 and automatically since the eighties. A wide variety of methods, which are now in operational use, have been tested at this site and new instruments are still under test here and at the Laret test site (1512 m above sea level), which was established in 2016.
The strong involvement of SLF in the international snow monitoring research community has been recognized in 2022 by the World Meteorological Organization (WMO), which designated SLF as the WMO-INFCOM Measurement Lead Centre - Snow Monitoring Competence Centre Davos (SMCC) to provide high-level expertise in both surface-based in situ instrumentation and remote sensing for monitoring key snow variables.