REKONSTRUKCJA DRENAŻU SUBGLACJALNEGO LODOWCA WERENSKIOLDA (SW SPITSBERGEN) NA PODSTAWIE MODELOWANIA NUMERYCZNEGO

Abstract

RECONSTRUCTING SUBGLACIAL DRAINAGE OF WERENSKIOLD GLACIER (SW SPITSBERGEN) BASED ON NUMERICAL MODELLINGAbstract. The paper attempts to describe subglacial drainage of the Werenskiold Glacier based on numerical modelling using FEFLOW software version 6.0. The model covers 36.2 km2 of a polythermal glacier basin, 75% of which is filled with ice (27.1 km2). Numerical modelling was preceded by field research carried out on Werenskiold during the summers of 2009-2011. The model illustrates the subglacial drainage in a ground moraine layer and the top of the bedrock. Permafrost and active layer of a maximum thickness of 2 m under the glacier snout and in its forefield were assumed (Replewska-Pękalowa, 2004). The aim of this study was to obtain the subglacial groundwater flow field and the spatial distribution of hydraulic pressures beneath the glacier and in its forefield. The spatial distribution of hydraulic pressure and groundwater flow paths beneath the glacier are controlled by its geometry (thickness), thermal conditions, the amount of ablation and rainfall water, and the hydrogeological parameters of the bed. The water flux in the ablation season in the aquifer under the glacier and in its forefield was estimated at 4624 m3/day, what corresponds to 8% of the seasonal ablation water and rainfall (5% of which drains through the sediments under the glacier). The remaining 92% of the ablation water is evacuated through in-and subglacial channel system.