Greenland ice sheet surface melt data set now available in Atlas of the Cryosphere

Release Date: July 17, 2007

The following Greenland surface melt data set is now provided in the Northern Hemisphere portion of the Atlas of the Cryosphere (under the Greenland basemaps pull-down menu):

The map that is provided shows the average number of days per year across the ice sheet that have had surface melt between 1979-2004. This annual climatology is derived from a daily (or every other day, prior to August 1987) estimate of the spatial extent of wet snow on the surface of the Greenland ice sheet derived from passive microwave satellite brightness temperature characteristics using the cross-polarized gradient ratio of Abdalati and Steffen (J. Climate, 1997). It is physically based on the changes in microwave emission characteristics observable in data from the Scanning Multi-channel Microwave Radiometer (SMMR) and the Special Sensor Microwave Imager (SSM/I). It is not a direct measure of the snow wetness but rather a binary indicator of the state of melt of each SMMR and SSM/I pixel on the ice sheet for each day of observation, a useful proxy for the amount of ablation that occurs on the Greenland ice sheet.

In addition to accessing this data set through the Atlas of the Cryosphere Web interface, it is also available remotely in a variety of formats and map projections through Open Geospatial Consortium (OGC) protocols, as in the following examples:

We welcome your feedback on this project. If you have questions, comments or suggestions, please contact NSIDC User Services at +1.303.492.6199,, or via our online contact form. The development of this map server application was supported by NASA's Earth Observing System (EOS) Program under contract NAS5-03099 and was developed using MapServer, an Open Source development environment for building spatially-enabled internet applications. The Atlas of the Cryosphere was developed by John Maurer. Future updates will continue to be announced on this RSS feed.


Abdalati, W. and K. Steffen. 1997. Snowmelt on the Greenland ice sheet as derived from passive microwave satellite data. Journal of Climate. 10(2): 165-175.