Greenland surface albedo changes in July 1981-2012 from satellite observations

Significant melting events over Greenland have been observed over the past few decades. This study presents an analysis of surface albedo change over Greenland using a 32-year consistent satellite albedo product from the global land surface satellite (GLASS) project together with ground measurements. Results show a general decreasing trend of surface albedo from 1981 to 2012 (-0.009 +/- 0.002 decade(-1), p < 0.01). However, a large decrease has occurred since 2000 (-0.028 +/- 0.008 decade(-1), p < 0.01) with most significant decreases at elevations between 1000 and 1500 m (-0.055 decade(-1), p < 0.01) which may be associated with surface temperature increases. The surface radiative forcing from albedo changes is 2.73 W m(-2) decade(-1) and 3.06 W m(-2) decade(-1) under full-sky and clear-sky conditions, respectively, which indicates that surface albedo changes are likely to have a larger impact on the surface shortwave radiation budget than that caused by changes in the atmosphere over Greenland. A comparison made between satellite albedo products and data output from the Coupled Model Inter-comparison Project 5 (CMIP5) general circulation models (GCMs) shows that most of the CMIP5 models do not detect the significantly decreasing trends of albedo in recent decades. This suggests that more efforts are needed to improve our understanding and simulation of climate change at high latitudes.