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Glacier length change observations

21.12.2009 | 12:21

Glacier length change observations record changes in the length of a central flow line in a glacier. A long length change record is also a proxy for glacier volume changes. During the 1990s many Norwegian glaciers advanced substanially. They represented a major discrepancy compared to the global pattern. After 2000, the Norwegian glaciers behave in accordance with the global pattern. 

Glacier length change is measured relative to fixed points as cairnes, bolts or marks painted on the rock surface. This mark is situated in front of Rembesdalsskåka, a western outlet from Hardangerjøkulen. Photo: Hallgeir Elvehøy. Glacier length change is measured relative to fixed points as cairnes, bolts or marks painted on the rock surface. This mark is situated in front of Rembesdalsskåka, a western outlet from Hardangerjøkulen. Photo: Hallgeir Elvehøy.


 

Results 2013

Length change observations performed at 33 glaciers show that 26 glaciers retreated and three glaciers advanced.

Background

Systematic glacier length change observations were initiated in 1899 and 1900 at Jostedalsbreen, Folgefonna Svartisen and in Jotunheimen. The measurements havee been performed by several different persons and institutions. NVE has been collecting, storing and publishing these measurements since 1994. The length change data are submitted to the World Glacier Monitoring Service (www. wgms.ch).  

Method

The distance is measured from established cairns or marks to the glacier front in the same direction every year. This gives an estimate of the glacier length change. These measurements have a degree of uncertainty both in the actual length determination, and to what extent the measurement is representative for the entire glacier terminus. Time-series of glacier length variation reflects changes in glacier volume.

Results 2010

Results from 31 glaciers show that 27 glaciers were retreating, one glacier showed no change, and three glaciers advanced. The largest retreat was found at Bødalsbreen in Stryn (65 meters), Steindalsbreen in Lyngen (40 meters) and Nigardsbreen in Luster (39 meters).

Results 2009

Twenty-seven glaciers were measured in 2009, five glaciers in North-Norway, and twenty-two glaciers in South-Norway. Twenty-two glaciers retreated. Kjenndalsbreen in Stryn retreated 93 meters, Fåbergstølsbreen in Jostedalen in Luster retreated 59 meters, and Bødalsbreen in Stryn retreated 52 meters. Langfjordjøkelen in Finnmark retreated 53 meters. At three glaciers the measurements indicated advance. One glacier had only minor changes (+/- 2 meters). Mean annual length change was 18 meters.

Results 2008

Thirty-two glaciers were measured in 2008, eight glaciers in North-Norway, and twenty-four glaciers in South-Norway. Twenty-four glaciers retreated. Fåbergstølsbreen in Jostedalen in Luster retreated 60 meters, and Brenndalsbreen in Stryn retreated 56 meters. Bondhusbrea, a western outlet from Folgefonna ice cap in Kvinherad retreated 50 meters. At three glaciers the measurements indicated advance. This is partly adjustments to relatively large changes in 2007. Five glaciers had only minor changes (+/- 2 meters). Mean annual length change was 14 meters. Measurements were resumed at three glaciers - Tunsbergdalsbreen in Jostedalen which was monitored between 1900 and 1965, and Trollkyrkjebreen (measured 1944 - 1974) and Finnanbreen (measured 1950-1974) at Trollstigen in Møre & Romsdal. 

Briksdalsbreen - revised glacier length record 1900-2006

Glacier length change measurements at Briksdalsbreen, a western outlet of Jostedalsbreen, started in 1900 (Rekstad 1902; 1904). Briksdalsbreen has had several periods of advances and retreats (Andreassen et al., 2005). Between 1932 and 1951 the terminus retreated more than 800 metres and uncovered the lake Briksdalsvatnet. The last advance started in 1987 and covered the lake entirely in 1997. Since 1999, the glacier has retreated rapidly, and by the end of 2006 the glacier terminus was at the upstream end of the lake again. Ideally, cumulative glacier length change should agree with distance between mapped glacier termini, and the cumulative glacier length should be the same in years when the glacier terminus is located in the same position. Some differences are due to the representativity of the measuring line and the changing shape of the tongue, as well as different dates of maps and photos (mainly obtained in summer) and glacier length observations (mainly in autumn). However, the differences between cumulative length change and surveyed or photographed changes have been considerable. To resolve this, the glacier length record of Briksdalsbreen has been revised. The analysis of the length change record is described in Chapter 13-2 in the 2006 annual report (download report as pdf). The revised series is available here.

Litterature (selected):

Andreassen, L.M., H. Elvehøy, B. Kjøllmoen, R. V. Engeset and N. Haakensen, 2005. Glacier mass balance and front variation in Norway. Annals of Glaciology, no 42, 317-325.

Fægri, K. 1940: Forandringer ved norske breer 1937-39. Bergen Museums Årbok 1939-40. Naturvidenskapelig rekke. Nr 3.

Hoel, A. & Werenskiold, W.1962: Glaciers and snowfields in Norway. Norsk Polarinstitutt Skrifter Nr.114, 291 p.

Kjøllmoen, B. (ed.), 2008: Glaciological investigations in Norway in 2007. NVE Report No.1, 91 p.

Liestøl, O. 1964. Noen resultater av bremålinger i Norge i 1963. Norsk Polarinstitutt, Årbok 1963., 185-192.

Rekstad, J., 1904: Fra Jostedalsbræen. Bergens Museums Aarbog 1904, No 1, 1-69.

Rekstad, J., 1910: Forandringer ved norske breer i aaret 1908-09. Bergens Museum Årbok 1910, 2-12.

Øyen, P.A., 1906: Klima- und Gletcherschwankungen in Norwegen. Zeitschrift fur Gletcherkunde, Eiszeitforschung und Geschichte. 1: 46-61. 

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