Mass balance measurements on Hintereisferner,Kesselwandferner and Jamtalferner2003 to 2006: database and results

摘要

The Hintereisferner, Kesselwandferner and Jamtalferner glaciers are subject to longterm mass balance programs. The results of the mass balance measurements 2003 to2006 are summarized and compared to the climate data measured at the nearby valleystations Vent and Galtur. The hot and dry summer of 2003 showed a positive deviation of the long termmean summer temperatures (1951-1980) of 2.6℃ in Vent and 2.8℃ in Galtur, giv-ing the most negative mass balance since beginning of the measurements for all threeglaciers. The mass balance of Hintereisferner in 2002/2003 was –1814 kg/m~2 which ismore than 3 times the long term average since 1953. In the following years the summer mean temperature was significantly closer tothe long term average. This resulted in less negative mass balances on Kesselwand-ferner and Jamtalferner, but on Hintereisferner the mass balance of 2005/2006 was-1516 kg/m~2 which is over 80% of the specific mass balance in 2002/2003.The equilibrium line altitude was above the summits in 2002/2003 on all threeglaciers, in 2004/2005 on Jamtalferner only and in 2005/2006 on Hintereisferner andKesselwandferner.The specific mass balances of one year differ from one glacier to the other, whichis a combined effect of glacier topography and precipitation. To answer the questionif single stakes on one glacier correlate with the total net balance of this glacier theablation on four stakes in five years on Hintereisferner was compared, showing thatdifferent stakes even on the same glacier do not reflect the annual results of the totalmass balance in the right order. In the recent years, the DEMs used for the calculation of mass balance changed.The results of the changes in database show that changes in total area and area of alti-tude zones can cause a bias in both the total balance and the altitudinal balance profile.This also affects the determination of the altitude of the equilibrium line, which isoften used for modelling climate change scenarios. Therefore, long term mass balanceseries should be well documented and regularly homogenized.