November 17, 2013
Steenstrup Glacier Retreat, New Island Generation NW Greenland
Posted by Mauri Pelto
Steenstrup Glacier is located at 75.2 N in Northwest Greeland. The glacier terminates on a series of headlands and islands, the glacier immediatley to the south is Kjer Glacier. The boundary between Steenstrup Gletscher and Kjer Glacier is Red Head, Steenstrup Glacier’s northern margin is at Cape Seddon. Here we examine changes in the terminus position of Steenstrup and Kjer Glacier from 1999 to 2013. The retreat of the glacier during this interval has led to generation of new islands. Steenstrup Glacier has retreated 10 km over the past 60 years (Van As, 2010). Kjer Glacier was noted as relatively stable until loss of connection with Red Head Peninsula in 2005 (Van As, 2010).
Image from Van As (2010).
McFadden et al (2011) noted several glaciers in Northwest Greenland Sverdrups, Steenstrup (75°16’15.37”N), Upernavik, and Umiamako that had similar thinning patterns. Each experienced rapid thinning of up to ~100 m a-1 since 2000. They further noted that thinning was not synchronous with Steenstrup and Sverdrups thinning fast from 2002 to 2005, Upernavik from 2005 to 2006, and Umiamako from 2007 to 2008. This is not exactly synchronous, but occurring within a few years is essentially synchronous in terms of glacier dynamics. Each glacier also had a coincident speed-up with a 20% acceleration for Steenstrup Glacier (McFadden et al, 2011). This is a familiar pattern with thinning there is less friction at the calving front from the fjord walls and the fjord base, leading to greater flow. The enhanced flow leads to retreat and further thinning, resulting in the thinning and the acceleration spreading inland. The initial thinning comes from a combination of basal and surface melt.
Here we examine Landsat images from 1999, 2001 and 2013 to identify changes. The red arrow indicates Red Head, which the glacier still reaches in 1999, though the connection is less than 2 km wide. The purple arrow indicates a small nunatak where the Automatic Weather Station utilized by Van As (2010) is located. The nunatak is 1.5 km from the ice edge in 1999. The orange arrow is an island at the ice front, South of the island the ice front is even with the island in 1999. The yellow arrow notes the connection of Steenstrup Glacier to Cape Seddon that is about 4 km wide. In 2001 there is little change in the ice front except at the purple arrow, where retreat has almost brought the nunatak to the terminus. By 2013 the connection to Red Head has been lost, it is now an island, this occurred as noted by Van As (2010) in 2005. Retreat from Red Head is 6 km. There is a substantial embayment south of the island at the orange arrow, indicating 4 km of retreat. North of this island that will soon lose it connection to the ice sheet, the embayment has expanded as well. At the purple arrow the ice front has reached the former nunatak now becoming an island. At the yellow arrow the loss in ice area at Cape Seddon is greater than at Red head, though a connection may still exist, it is too narrow to measure. The last image below is a 2012 Google Earth image indicating the narrow connection to Cape Seddon at that time and the strange relict crevasse pattern. It is clear that the end of Cape Seddon will be in island next summer if not already, the MODIS imagery is not clear enough to distinguish this. The connection to the island at the south end of Kjer Glacier, last yellow dot near bottom has become much narrower since 1999 and will follow the route of Red Head and Cape Seddon. The retreat here is coincident with the thinning and acceleration and follows the pattern of retreat and new island generation seen at Kong Oscar Glacier, Alison Glacier and Upernavik Glacier.
2013 Landsat image
Google Earth 2012 image Cape Sneddon, how long will it last?
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