Geophys. Res. Lett. http://doi.org/jhb (2012)

In the summer of 2012 the Greenland Ice Sheet experienced an extreme melt event. Research led by NASA scientists used data from three different satellite sensors to create a composite melt map of the Greenland Ice Sheet. It reveals that melting had occurred at or near the surface of 98.6% of the icesheet on 12 July 2012. This result was verified by comparison with weather station temperature data.

The likely cause of the extreme melt was an anomalous ridge of warm air that stagnated over Greenland. Study of ice core records in the literature revealed that such a major melt event is rare, with the last occurrence in 1889 and the next earlier in the Medieval Warm Period.

This study highlights the capability of using data from several satellites for the most complete melt detection, providing tools for future climate research.