Effect of artificial snow cover on the mass balance of the Morteratsch glacier

Abstract

The glacier Vadret da Morteratsch has been losing mass rapidly in the past century. A proposed solution to its retreat is the deposition of artificial snow made from meltwater to the glacier surface. The effects of this solution are analyzed using a mass and energy balance model of the Morteratsch glacier. The model uses input from nearby weather stations and is tuned using data from the Automatic Weather station on the glacier. In the reference run, three mass balance years from 2016-2019 are analyzed. During this period, the modelled mass balance of Morteratsch glacier is -0,80 m w.e./yr. In the experimental runs, artificial snow is deposited to the glacier surface for wet bulb temperatures below -2 $^oC$. The artificial snow supply is constrained to an area of 0,8 km$^2$ on the glacier tongue. When there are no limitations to the amount of water used, the glacier mass balance can be increased to +0,14 m w.e./yr with artificial snow deposition in this area. In practice, it is uncertain whether enough meltwater can be stored throughout the year. If artificial snow supply is constrained by a water reservoir of 10$^6$ m$^3$, the mass balance becomes -0.42 m w.e./yr. Running the model with a reservoir of 10$^4$ m$^3$ results in a mass balance of -0.68 m w.e./yr.