In this post we are presenting some findings about the retreat of Tunsbergdalsbreen glacier.
An examination of Tunsbergdalsbreen in Landsat imagery reveals glacier retreat from 1989 to 2014. These findings are available in the "From a glaciers perspective" blog, by Mauri S. Pelto who is a professor of environmental science at Nichols College in Dudley, Massachusetts and director of the North Cascades Glacier Climate Project.
The post about Tunsbergdalsbreen was originally published in February 2012. After an email exchange of information between The Norwegian Glacier Museum and professor Pelto, the post was updated with a Landsat imagery from 2014 and photos of the glacier terminus from 2013.
The important findings from this examination are clear evidences on negative length changes and a thinning of the glacier, which indicates a negative mass balance.
In the Landsat image from 2014 you clearly see a proglacial lake at the terminus that didn't exist in 1989. From 1989 to 2014 this lake grew 700 metres long, see the purple arrows.
Exposure of bedrock is also evident over the time period, which is a result of an ongoing thinning of the ice, as indicated by the green arrows. An increasing snowline (which indicate the equillibrium line) is a concern for sustaining the glacier.
We thank professor Pelto for kindly giving us permisson to publish these findings on our website. Check out his blog, "From a glaciers perspective" for more detailed information and interesting reading about other glaciers from around the world.
The retreat of Tunsbergdalsbreen, as common with most glaciers world wide, is a long term trend. This is known through several previous investigations of the glacier. By compiling earlier works and maps of Tunsbergdalsbreen, students connected to the Tunsbergdalsbreen Project has produced maps of the glacier extent at different stages.
The map in figure 3 shows glacier extent from 1743 to 1995. The curved lines represent former terminal morraines. Note that the extent goes into a lake. This is a dammed reservoir for hydro power built in 1978.
In figure 4 you see a detailed map of Tunsbergdalsbreens extent and geomorphology in the glacier foreland from 1908 to 2010.
These maps are just a few examples of what young and clever participants in Tunsbergdalsbreen Project has produced over the years. Many of the expedition members have been students at bachelor level, using data from field work in their own dissertations.
Stay tuned for more news about our Tunsbergdalsbreen Project.