Impact of boundary conditions on the modelled thermal regime of the Antarctic ice sheet
Abstract. A realistic initialization of ice flow models is critical for predicting future changes in ice sheet mass balance and their associated contribution to sea level rise. The initial thermal state of an ice sheet is particularly important as it controls ice viscosity and basal conditions, thereby influencing the overall ice velocity. Englacial and subglacial conditions, however, remain poorly understood due to insufficient direct measurements, which complicates the initialization and validation of thermal models. Here, we investigate the impact of using different geothermal heat flux (GHF) datasets and vertical velocity profiles on the thermal state of the Antarctic ice sheet, and compare our modeled temperatures to in situ measurements from 15 boreholes. We find that the vertical velocity plays a more important role in the temperature profile than GHF. More importantly, we find that the standard approach, which consists in combining basal sliding speed and incompressibility to derive vertical velocities, provides reasonably good results in fast flowing regions (ice velocity > 50 m yr-1), but performs poorly in slower moving regions.
Viewed (geographical distribution)