Satellite Data Indicates Unprecedented Greenland Ice Sheet Surface Melt

ASA says new satellite measurements indicate unprecedented recent Greenland ice sheet surface melt. The images above show the extent of surface melt over Greenland’s ice sheet over just a four day period - from July 8 (left) and July 12 (right). Measurements from three satellites showed that on July 8, about 40% of the ice sheet had undergone thawing at or near the surface. This melting dramatically accelerated to an estimated 97% of the ice sheet surface by July 12. On average in the summer, about half of the surface of Greenland's ice sheet naturally melts. The colors in the above image are classified as follows: light gray (ice snow/free), light pink (probably melt) and dark pink (melt). You can see a larger version of the image here

NASA says the areas classified as "melt" (dark pink) correspond to sites where two or three satellites detected surface melting. NASA says the satellite images provide a picture of an extreme melt event about which scientists are very confident. 

Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data, says, "Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time. But if we continue to observe melting events like this in upcoming years, it will be worrisome." 

Image: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory