Tunsbergdalsbreen Glacier Retreat, Norway

February 27, 2012 at 1:17 am · Filed under Glacier Observations ·Tagged Jostedalsbreen glacier retreat, norway glacier retreat, Tunsbergdalsbreen glacier retreat

The Norwegian Water Resources and Energy Directorate (NVE) has an excellent glacier monitoring program. In 2011 the terminus survey looked at 31 glaciers that have been consistently monitored , 27 retreating, 2 stable and 2 advancing. Of these ten drain the largest ice cap in Norway the Jostedalsbreen, from 2008-2011 the net change was retreat on all 11. The largest outlet glacier Tunsbergdalsbreen is not one of the closely monitored glaciers. This glacier flows southeast from the icecap, is 18 km long and terminates at 670 meters in a new proglacial lake. Examination of Tunsbergdalsbreen in Landsat imagery from 1989 (top), 2003 (middle) and 2010 (bottom) illustrates retreat of the terminus of 450 meters and thinning upglacier exposing new areas of bedrock. The violet arrows indicate the terminus. In 1989 no lake is evident. By 2003 the lake has begun to develop and in 2010 the lake is 400 meters across. The glacier is fed by several tributaries coming off the ice cap. At the #3 green arrow, bedrock is now exposed in the midst of an icefall from the upper ice sheet that was underneath the glacier in 1989 and 2003. At green arrows #1 and #2 the area of bedrock exposure is expanding, indicating less ice draining from the ice cap into the tongue of the Tunsbergdalsbreen. A closeup of the terminus from Google earth indicates that a second lake has begun to form at the terminus. This combined with the observed thinning upglacier indicates that retreat will continue. Exposure of bedrock upglacier occurs because of thinning, which only occurs because of mass balance loss which also results in velocity and discharge reductions. In 2010 and 2011 glacier mass balances across Norway were negative. At present the Tunsbergdalsbreen is the focus of a new project that aims to begin monitoring the glacier on an annual basis. This project is focussing on monitoring the elevation of the glacier surface, the ice velocity and the front position. Photographs of the project are also worth examining.

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