Jun 28, 2017
Decreasing cloud cover drives the recent mass loss on the Greenland Ice Sheet
by
,
Science Advances
- States that the Greenland Ice Sheet (GrIS) has been losing mass at an accelerating rate since the mid-1990s
- States that this has been due to both increased ice discharge into the ocean and melting at the surface, with the latter being the dominant contribution
- States that this change in state has been attributed to rising temperatures and a decrease in surface albedo
- Shows, using satellite data and climate model output, that the abrupt reduction in surface mass balance since about 1995 can be attributed largely to a coincident trend of decreasing summer cloud cover enhancing the melt-albedo feedback
- Satellite observations show that, from 1995 to 2009, summer cloud cover decreased by 0.9 ± 0.3% per year
- Model output indicates that the GrIS summer melt increases by 27 ± 13 gigatons (Gt) per percent reduction in summer cloud cover, principally because of the impact of increased shortwave radiation over the low albedo ablation zone
- Finds that the observed reduction in cloud cover is strongly correlated with a state shift in the North Atlantic Oscillation promoting anticyclonic conditions in summer and suggests that the enhanced surface mass loss from the GrIS is driven by synoptic-scale changes in Arctic-wide atmospheric circulation