Why we monitor snow cover—and what does it have to do with our climate?

Snow is an important component of the hydrological cycle. Snow cover is defined as the area of land covered by accumulated snow. It regulates the Earth’s temperature; like a cool pack and a blanket at once.

While snow is there, it reflects the sun’s radiation back into the atmosphere, thereby keeping the Earth cool. Additionally, it covers the ground below, keeps it moist and warm for organisms. Furthermore it delays the melting of permafrost, effectively preventing the release of sequestered carbon and fueling of the greenhouse effect.

Once snow melts, it fills rivers and lakes in valleys and basins. It is an important water supply for people. Changes in snow cover have significant effects on our environment and ecosystems. On average, 45 Mio. km2 of the Earth’s surface are periodically covered by snow. Knowing the accurate snow extent is key for climate studies, weather forecasting, reservoir management, electric power production and winter tourism. Mapping snow extent is important.

State-of-the Art

The derivation of snow extent from medium resolution optical satellite data is the state-of-the-art. It allows for a timely coverage of large areas. While various methods for snow mapping exist, all of them suffer from gaps due to clouds or sensor capacity. These gaps degrade the quality and usefulness of the products.

Especially in the melting period, with high temporal and spatial variability in snow extent, cloud-cleaned products are of high interest for hydrology and water management.

Satellite image (Sentinel-2), Austrian Alps


In this project, Catalysts exploits the novel Copernicus Sentinel-3 mission with its SLSTR and OLCI instruments for snow mapping. Sentinel-3 data acquisition is designed to work very well in continuation of recent ENVISAT AATSR and MERIS missions, as well as NASA’s MODIS instrument, which have previously been used for the creation of snow products.

Based on the Sentinel-3 data and the inclusion of additional meteorological data, we will continuously generate cloud-cleared maps of snow cover without observation gaps. Demonstration products will be made available stepwise for the Alpine region, the pan-European continent and the northern hemisphere.

Snow coverage of Mittersill, 01.03.2012 to 31.05.2012

This project is carried out in a partnership of Catalysts and ENVEO and is funded by the European Space Agency (ESA).

Logo of Catalysts
Logo of ENVEO
Logo of ESA

Satellite data processing belongs to our field of expertise

  • Are you an environmental scientist?
  • Or a climate enthusiast?
  • Or would you simply like to know, where the conditions are best for your next ski hiking tour?

Feel free to contact us. We are always looking for new challenges.

Your contact person

Michael Aspetsberger

High Performance Computing


Profile on Skype

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