Studying the effects of strain heating on glacial flow within outlet glaciers from the Heimefrontfjella Range, D.M.L., Antarctica.

A one-dimensional numerical thermodynamic model is used to study the effects of strain heating on temperature profiles along the flowline of two outlet glaciers in Dronning Maud Land, Antarctica. Measurements of ice surface velocities on the glaciers show higher speeds (and lower ice viscosity) than surface speeds calculated using Glen's flow law. These calculations are based on ice temperature distributions excluding strain heating in the general heat equation. The incorporation of strain heating in the general heat equation produces higher ice temperatures, and calculated ice surface speeds that match the measured values. It is found that relatively short scale temporal and spatial steps in basal topography are enough to drive the ice flow into a positive feedback loop as long as the bedrock step produces a stress that overcomes the advection of cool ice from the surface. In this case, where surface temperatures are -25 degrees C stresses of 0.4 MPa are enough to drive the base of the ice to the melting point within 100 years.