We use internal ice layers from a radio echo-sounding profile between the Kohnen and Dome Fuji deep drilling sites to the infer the spatio-temporal pattern of accumulation rate in this sector of Dronning Maud Land. Continuous internal reflection horizons can be traced to about half the ice thickness and have a maximum age of ca. 70 ka BP. We have selected 7 time intervals over which we determine the average accumulation rate and average surface temperature at the place and time of origin of the layer particles. The layers are destrained from a rigorous flow calculation with a high-resolution higher-order flow model of Dronning Maud Land nested into a 3D thermomechanical model of the Antarctic ice sheet ran over the last few glacial cycles. A Lagrangian back-tracing algorithm provides the places of deposition of the layers along the profile to correct for flow advection. Further corrections are made for local elevation changes. Our results show substantially lower accumulation rates along the profile than shown by exisiting maps which had no surface control points. During the last glacial period we find a substantially lower accumulation rate than predicted by the usual approach linking palaeo-accumulation rates to the condensation temperature above the surface inversion layer. This finding helps to improve flow reconstructions of this area over the last glacial cycles and enables a more accurate dating by flow modeling of the EDML ice core.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL1-Processes and interactions in the polar climate system
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene