July 4, 2012
Olsokbreen Retreat, Svalbard
Posted by Mauri Pelto
Svalbard is host to 163 tidewater glaciers with a collective calving front of 860 km (BŁASZCZYK et al, 2009). The southernmost of these glaciers on the west coast of Sørkappland is Olsokbreen, purple arrow.
Olsokbreen has a 5 km calving front and its retreat was observed to have retreated 3.5 km from 1900-2008 (Zjaja et al, 2008). Here we examine Landsat imagery from 1990 and 2014 and Geoeye from 2012 to illustrate a significant change in the ice front of Olsokbreen in the last 25 years. The glacier has pulled back from a peninsula extending into the sound from the north side of the fjord that the glacier ended upon in 2002, red arrow. In the 2002 image the 2010 ice front is noted with a violet arrow as is an area of proglacial lakes that become more evident in 2010. In 2010 there is a relatively straight north-south calving front has become quite irregular during the 300-1100 meters of retreat along the ice front. A substantial proglacial lake has developed by 2010, along the southern margin of the glacier. The 2012 image is a Geoeye image and the main changes from 2010 is the extension of open water at the north side of the glacier between the terminus and the peninsula. This extends the calving front width and should increased calving. The southern edge has experienced more retreat since 2010 with the angular shaped calving embayment, green arrow. A comparison of 1990 and 2014 Landsat images indicates the full scope of the retreat at 4.8 km along the southern margin and 1.2 km on the northern margin. This retreat is larger than for Vasileevbreen, Samarinbreen or Hambergbreen-Hornbreen.
1990 and 2014 Landsat Images. Red arrows mark the 1990 terminus positions
2002 Landsat Image
2010 Landsat image
2012 Geoeye Image
The Olsokbreen like the nearby Hambergbreen and Hornbreen is retreating and thinning.This glacier would seem to be particularly prone to impacts from warming water in the Barents Sea. In 2011 the ocean heat flux (Walczowski, 2011) passing Olsokbreen illustrates this. The sea ice off of Olsokbreen has also been exiting earlier as is evidenced in a recent image sequence from the Arctic Sea Ice Blog.