Langfjordjokelen, a rapidly shrinking glacier in northern Norway

In this paper we document changes of Langfjordjokelen, a small ice cap in northern Norway. Surface mass-balance measurements have been carried out on an east-facing part (3.2 km(2)) of the ice cap since 1989. Measurements reveal a strong thinning; the balance year 2008/09 was the 13th successive year with significant negative annual balance (<=-0.30 m w.e.). The average annual deficit was 0.9 m w.e. over 1989-2009. The recent thinning of Langfjordjokelen is stronger than observed for any other glacier in mainland Norway. Maps from 1966, 1994 and 2008 show that the whole ice cap is shrinking. The total volume loss over 1966-2008 was 0.264 km(3). The east-facing part has been greatly reduced in volume (46%), area (38%) and length (20%). For this part over 1994-2008, the cumulative direct mass balance (-14.5 m w.e.) is less negative than the geodetic mass balance (-17.7 m w.e.). A surface mass-balance model using upper-air meteorological data was used to reconstruct annual balances back to 1948 and to reconstruct unmeasured years 1994 and 1995. Sensitivity of annual balance to 1 degrees C warming is -0.76 m w.e. and to 10% increase in precipitation is +0.20 m w.e.