Spatio-temporal variability in geometry and geodetic mass balance of Jostedalsbreen ice cap, Norway
Liss M. Andreassen, Benjamin Aubrey Robson, Kamilla Hauknes Sjursen, Hallgeir Elvehøy, Bjarne Kjøllmoen, Jonathan L. Carrivick
Abstract
Abstract The Jostedalsbreen ice cap is mainland Europe's largest ice cap and accommodates 20% (458 km 2 in 2019) of the total glacier area of mainland Norway. Jostedalsbreen and its meltwater contribute to global sea-level rise and to local water management, hydropower and tourism economies and livelihoods. In this study, we construct a digital terrain model (DTM) of the ice cap from 1966 aerial photographs, which by comparing to an airborne LiDAR DTM from 2020, we compute changes in surface elevation and geodetic mass balances. The area mapped in both surveys cover about 3/4 of the ice cap area and 49 of 82 glaciers. The measured glacier area has decreased from 363.4 km 2 in 1966 to 332.9 km 2 in 2019, i.e. a change of −30 km 2 or −8.4% (−0.16% a −1 ), which is in line with the percentage reduction in area for Jostedalsbreen as a whole. The mean geodetic mass balance over the 49 glaciers was −0.15 ± 0.01 m w.e. a −1 , however, large variability is evident between glaciers, e.g. Nigardsbreen (−0.05 m w.e. a −1 ), Austdalsbreen (−0.28 m w.e. a −1 ) and Tunsbergdalsbreen (−0.36 m w.e. a −1 ) confirming differences also found by the glaciological records for Nigardsbreen and Austdalsbreen.