Simulation of the Antarctic ice sheet with a three-dimensional polythermal ice-sheet model, in support of the EPICA project. II. Nested high-resolution treatment of Dronning Maud Land, Antarctica

摘要

The modern dynamic and thermodynamic state of the entire Antarctic ice sheet is computed for a 242 200 year paleoclimatic simulation with the three-dimensional polythermal ice-sheet model SICOPOLIS. The simulation is driven by a climate history derived from the Vostok ice core and the SPECMAP sea-level record. In a 872 km x 436 km region in western Dronning Maud Land (DML), where a deep ice core is planned for EPICA, new high-resolution ice-thickness data are used to compute an improved bedrock topography and a locally refined numerical grid is applied which extends earlier work (Calov and others, 1998). The computed fields of basal temperature, age and shear deformation, together with the measured accumulation rates, give valuable information for the selection of a drill site suitable for obtaining a high-resolution climate record for the last glacial cycle. Based on these results, a possible drill site at 73° 59' S, 00° 00' E is discussed, for which the computed depth profiles of temperature, age, velocity and shear deformation are presented. The geographic origin of the ice column at this position extends 320 km upstream and therefore does not leave the DML region.