April 16, 2015
Langfjordjokulen, Norway Retreat-Thinning
Posted by Mauri Pelto
Langfjordjokulen is in the Finnmark region of northern Norway. This is a plateau glacier with a valley glacier extending east toward Langfjordhamm. The Norwegian Water Resources and Energy Directorate has monitored the length change and mass balance of this glacier from 1989-2014. The mean mass balance has been significantly negative averaging -0.7 m/year, with every year being a net loss since 1997. This is no way to sustain a glacier or a business. Retreat of the glacier has averaged 27 m/year from 2000-2014. Here we examine Landsat imagery of the glacier from 1989-2014 to identify key changes.
In 1989 the glacier terminated at the red arrow, two glacier tongues descended from the plateau and merged below the purple arrow indicating the northern arm. A ridge extends some distance into the main plateau separating the catchment areas of the two glacier tongues, marked by the letter A. The glacier is mainly snowcovered in August 1989 and had a negative mass balance of -0.55 m. In 1994 the two glacier tongues are still joined, and snowcover is extensive, retreat is limited since 1989. In 2000 snowpack is quite limited at the time of the image, the two glacier tongues have separated and the main terminus has retreated from the red arrow. In 2014, Norway’s warmest year, snowpack retained is minimal, the glacier mass balance reported by NVE to the World Glacier Monitoring Service was -0.78 m, an improvement over the record low year of 2013, -2.61 m. A new area of bedrock is emerging near Point A, due to glacier thinning in the plateau area which should be the accumulation zone. The two glacier tongues are further separated. The main terminus is at the yellow arrow a retreat of 600-700 m since 1989. This retreat rate is faster than other periods since 1900. The retreat is similar to that of the larger nearby Strupbreen and Koppangsbreen. The cumulative mass loss experienced by Langfjordjokulen is a significant portion of its total volume, 25-35% assuming typical glacier thickness for a glacier with this area. In 2014 NVE reported In Norway terminus fluctuation data from 38 glaciers with ongoing assessment indicate, 33 retreating, and 3 were stable. The average terminus change was -12.5 m