Model study of the spatial distribution of the energy and mass balance of Morteratschgletscher, Switzerland

To investigate the spatial distribution of the energy- and mass-balance fluxes of a glacier, a two-dimensional mass-balance model was developed and applied to Morteratschgletscher, Switzerland. The model is driven by meteorological input from four synoptic weather stations located in the vicinity of Morteratschgletscher. The model results were compared to observations made on the glacier. The calculated mean specific mass balance is -0.47 m w.e. for 1999, and 0.23 m w.e. for 2000. Net shortwave radiation shows a minimum at around 3350 m a.s.l., due to the effects of shading, slope, aspect, reflection from the slopes, and obstruction of the sky. Ignoring these effects results in a 37% increase in the annual incoming shortwave radiation on the glacier, causing 0.34 m w.e. more ablation. A 1degreesC change in the air temperature results in a shift of 0.67 m w.e. in the mean specific mass balance, while altering the precipitation by 10% causes a change of 0.17 m w.e.