Satellite Snow Product Intercomparison and Evaluation Experiment


SnowPEX is an international collaborative effort, funded by the European Spcae Agency (ESA), aiming to intercompare and evaluate satellite-based seasonal snow cover products of hemispheric to global extent in order to assess their accuracy, resolve possible discrepancies and elaborate guidelines for further improvement.


Seasonal snow is a main element of the global water cycle and climate system. Due to its strong influence on the radiation and energy balance, changes in snow extent tend to amplify climate fluctuations. Terrestrial snow covers up to 50 million km2 of the Northern Hemisphere in winter and is characterized by high spatial and temporal variability. Therefore satellite observations provide the only means for timely and complete observations of the global snow cover. The recently published 2013 IPCC Working Group 1 report identifies a clear trend of decrease in seasonal snow extent during the recent decades. The importance of accurate data on the global snow cover has been addressed in the WCRP-CliC Workshop and "WCRP Grand Challenges and the Cryosphere in a Changing Climate", held in Tromsö, 16-18 Oct. 2013. In order to improve the knowledge of the temporal dynamics and physical properties of snow as a component of the coupled climate system, the need to "produce better global-scale datasets of snow cover, SWE, and snow thermal properties by drawing together local and remote sensing observations" has been identified as an important goal". Also in the WMO Global Cryosphere Watch Workshop in January 2013 the need of evaluating and consolidating snow products based on different satellite sensors and retrieval methods was identified.


This projects aims to bring together scientists and institutions active in generation of hemispheric to global seasonal snow cover products in order to assess the quality of current snow products derived from satellite data, resolve possible ambiguities and work out guidelines for improvement.

The primary objectives are

  • Intercompare and evaluate global / hemispheric (pre) operational snow products derived from different EO sensors and generated by different algorithms, in order to assess the product quality by objective means.
  • Identify communalities and discrepancies in the various satellite snow products, and determine their causes
  • Evaluate and intercompare temporal trends of seasonal snow parameters derived from different EO based products in order to achieve well-founded estimates of reliability for climate change monitoring
  • Elaborate recommendations for further improvements in methods, processing lines and delivery of snow products from EO data.


Dr.Thomas Nagler


Technikerstrasse 21a

6020 Innsbruck Austria 
Dr. Bojan Bojkov
Via Galileo Galilei Frascati (RM)
00044 Italy