Graph of the Day: Seasonal Melt Departure and Maximum Temperature Anomaly in Greenland, 1973-2007
(a) Seasonal Melt Departure (SMD) for June-August and (b) seasonal maximum daily temperature anomalies at three coastal meteorological stations in Greenland for June-August from 1973 to 2007 (Mote 2007). The recent marked retreat, thinning, and acceleration of most of Greenland’s outlet glaciers south of 70° N has increased concerns over contributions from the Greenland Ice Sheet to future sea-level rise (Howat et al. 2005). These rapid changes seem to be parallel to the warming trend in Greenland, the mechanisms are poorly understood. An analysis of a large sample of southern Greenland Ice Sheet marine- and land-terminating outlet glacier thinning rates showed that more than 75 per cent of marine-terminating outlet glaciers are thinning significantly more than their land-terminating counterparts. There was a dramatic increase in almost all marine outlet glacier thinning rates from 1993 to 2006, when the documentation ended, suggesting a widespread forcing mechanism. These findings suggest that a change in a controlling mechanism specific to the thinning rates of marine-terminating outlet glaciers occurred in the late 1990s and that this change did not affect thinning rates of land-terminating outlet glaciers (Sole et al. 2008).
