The Norwegian Water Resources and Energy Directorate (NVE) is annually monitoring a number of Glaciers in Norway. Tunsbergdalsbreen was originally part of this program, until 1972. Its remote position and the difficult accessibility were the reasons why it was taken out of the program. Through the Tunsbergdalsbreen Project, the glacier rejoined the monitoring program in 2008.
Front position, ice velocity and elevation of the glacier surface are changing from year to year. These changes reflect to a certain extent the changes in climate. The intention of Tunsbergdalsbreen Project is to monitor the changes of these three factors from year to year, although weather conditions might hinder certain tasks to be carried out every year. The results of the monitoring program will among others be presented at the Norwegian Glacier Museum in Fjærland, Norway and on this project website.
Since the field work has to be carried out within the borders of the Jostedalsbreen National Park, all the arrangements for the field work activity must be approved by the National Park Authorities (SNO and Fylkesmannen i Sogn og Fjordane).
The front position is measured by taking the distance from permanent marks on bedrock in the area in front of the glacier snout to the glacier front, using GPS, compass and laser distance meter.
The ice velocity is measured by putting out marked stones forming profiles across the glacier tongue. Permanent marks on the bedrock to both sides of the glacier enable us to establish the rows of stones accurately every year. Then we have to try to find again all the stones of the profile brought out last year, in order to measure the distance every stone has covered within the last year, moving downhill on the ice. For this task we use GPS, rocks we find in the area, paint and laser distance meter or measuring tape.
Elevation of the glacier surface
The elevation of the glacier surface is measured annually on the lower part of the glacier. In the area between the equilibrium line (the snow line in the autumn) at 1200m asl. and the ice fall at approx. 900m asl. the elevation may be measured less frequently, but always for a minimum of 2 successive years together.
Accurate elevation measurements are taken using specialist surveying dGPS equipment, following the same tracks as previous years, and taking many individual readings, which enables us to calculate the average loss (or gain) of ice thickness each year at various altitudes. Progressively over a long period, the pattern of these annual changes will help to show how the ongoing change in climate is affecting the glacier.
We also hope to be able to link this new data to surveys of the glacier done before 1972, to find out how the surface has changed since the 1950s.
We have photographs of the glacier from the 1950s taken from the ridge southeast of the glacier. From the very same spots, we re-take the pictures every year and in this way also document the changes of the glacier. We also take pictures of the glacier front.