A New Global Climatology of Ephemeral and Seasonal Snow

The growing catalogue of historical snow records includes a breadth of data derived from in-situ records, satellite remote sensing observations, global-scale models or reanalysis, and, in some cases, a combination of all three. Nonetheless, there have been limited efforts in recent decades to provide a synthesis of such datasets to develop a reliable global snow climatology. Updated records of snow capturing its distribution for the recent climatological period are needed to support a range of end-user applications (e.g., mobility, ecology, water supply, etc.). Such a climatology should include historical summaries of snow-covered area (SCA), snow depth (SD), and SWE estimates at a hemispheric extent as well as nontraditional metrics such as snow regime inter-annual variability. To achieve this, we optimally combine snow records into a new climatology that captures SCA, SD, and SWE at approximately 10 km resolution globally. Also, using snow cover, we identify and classify different snow regimes with new global high-resolution masks (1 km) for the recent climatological period. Here, we will present processing steps, new global maps of snow properties and snow regimes, and information on data availability and dissemination to the broader snow community. The resulting dataset can serve as a valuable input for long term planning, as a baseline input for downscaling of snow data, and to inform the selection of climatologic proxies by providing historical context for what can be considered 'normal' snow conditions.