Energy and mass balance of the Mandrone Glacier (Adamello, Central Alps)

The Adamello Glacier is the largest glacierised area in the Italian Alps and consists of five hydrographic units, the major in size being the Mandrone Glacier which covered an area of 13.38 km2 in June 2003. In order to assess the yearly mass balance of the Mandrone Glacier the PDSLIM energy-balance model was applied: it is a seasonal snowpack model, adapted to glaciers and based on a distributed physically based two-layer snow and ice scheme. In this paper the investigated area, the model and the hydrometeorological data used in input to the model and for its verification are described. On a large scale, the accuracy of the model in simulating the retreat of the snow covered areas during the melt season is verified through comparison with remote images, resulting in a 86% correspondence of observed snow-covered pixels. Downstream runoff measurements at the outlet of the Sarca di Genova basin at the Ponte Maria station were used as a term of comparison of the simulated summer melt. Runoff volumes measured over a twelve year period (1995- 2006) were used to validate the simulation of the glacier’s melt, resulting in a correlation coefficient of 0.83. The mean annual mass balance of the Mandrone Glacier over the 1995-2006 period results in an average water equivalent net loss of 1290 mm a-1, with a maximum value of 319 mm for the 2000/01 balance year and a minimum value of –3050 mm for the 2002/03 year.