Depth profiles of effective viscosities of temperate firn following from strain rate measurements at two firn pits (Kesselwandferner, Oetztal Alps, 1967–1989)

Abstract

From strain rate measurements at two firn pits, the effective shear viscosity and the effective bulk viscosity for temperate firn of high density were calculated, depending upon the depth and the in-situ state of stress. At densities from 640 to 840 (kg/m 3) the effective shear viscosity increases from 0.2×10 10 to 1.5×10 10 (kPa s) and the effective bulk viscosity from 4.4×10 10 to 65.1×10 10 (kPa s). From these viscosities, the effective compative viscosity and the effective uniaxial viscosity were calculated and compared with the values of other types of snow.