December 6, 2012

Qaleraliq Glacier Retreat, Southern Greenland

Posted by Mauri Pelto

Qaleraliq Glacier is in southern Greenland and flows into the Tasermiut Fjord. Glaciers in this region have experienced substantial retreat since 1990 Weidick et al (2012) and Howat and Eddy (2011). Howat and Eddy (2011) state that, “We find that 90% of the observed glaciers retreated between 2000 and 2010, with rapid retreat observed in all sectors of the ice sheet. The current retreat is accelerating and likely began between 1992 and 2000, coincident with the onset of warming, following glacier stability and minor advance during a mid-century cooling period.” In this case we are examining a tidewater glacier in Southern Greenland using satellite imagery from 1992, 2004, 2010 and 2012. In each image locations A-D are in the same locations marking specific bedrock islands (nunataks) within the ice sheet. The yellows arrows indicate the 1992 terminus position in each image, the black arrow denotes the terrain south of bedrock nunatak B. Retreat of the west arm of the glacier has been 3.2 km from 1992 to 2012. The east arm retreat in the last twenty years has been 1.2 km. In 1992 Nunatak A is 1.5 km from the ice edge and is composed of two separate nunataks. By 2010 the two nunataks have merged and by 2012 Nunatak A is 1 kilometer from the ice edge. In 1992 Nunatak B is 3 km from the icefront surrounded by the ice sheet and in 2012 the nunatak has increased in size and extends 1 km beyond the terminus. Nunatak C has largely emerged from the ice sheet, the nunatak has also expanded in length by 500 meters as ice has thinned during the retreat. The Nunatak at D did not exist in 1992, but by 2012 it is over 1 km long.
qaleraliq 1992
qalaeriq ge
qaleraliq 2010
qaleraliq 2012
A close up view of the terminus and Nunatak B and C from 1992 and 2012 illustrates the expansion of the nunataks as ice has thinned. The locations at the green and purple arrows are the same in both images. In 1992 these locations are near the nunatak margin and by 2012 the locations are in the midst of the Nunatak. Qaleraliq Glacier behavior is similar to that of almost all southern Greenland glaciers, most of which like Qaleraliq have not been the focus of detailed study, such as Kuussuup Sermia, Narssap Sermia or Kangiata Sermia. In the Tasermiut Fjord Biggs (2011) noted the retreat of two glaciers Sermitsiaq and Itillersuaq that have each retreated 600 and 300 m respectively from 1987 to 2009.qualeraliq glacier 1992The unusual nature of the 2012 melt season can be seen in this animated graph of ice sheet melt extent with data from Marco Tedesco, Figure 2a in the recent paper submitted (Tedesco et al, 2012).[youtube=]

qualeraliq glacier 2012