Prediction of thermodynamic state of the Gregoriev ice cap, Tien Shan, central Asia, in the future

Abstract

We use a two-dimensional flowline model to study the flow of the Gregoriev ice cap, Tien Shan, central Asia. The model takes into account the transverse change of glacier width, data on the measured thickness of the glacier, the surface velocity at the glacier front, and mass-balance measurements in 1987 and 1988. The calculated ice velocity varies from 0 to 3 m a-1 along the glacier flowline. The velocity maximum is shifted from the lowest part towards the middle part of the ice cap for the time interval considered (1980-2050) in the study. The derived changes of the glacier show the degradation and decrease of glacier extent on the south slope of Terskey Ala Tau, Tien Shan. Seasonal variations of temperature in the subsurface layer result in oscillations of stresses and velocities that are due to seasonal changes of viscosity. The consequent stresses can exceed the compressive/tensile strength that would produce crevasses.