Numerical simulation of ice-dynamic properties around the EPICA DML drill site with a nested Antarctic ice sheet model

• Main Authors: Huybrechts, Philippe, Rybak, Oleg, Pattyn, F., Steinhage, Daniel
• Format: Conference Object
• Language: unknown
• Published: 2003
• Subjects: Antarctic; The Antarctic; Dronning Maud Land; Antarc*; DML; EPICA; ice core; Ice Sheet; Ice Shelf
• Online Access: https://epic.awi.de/id/eprint/9000/; https://hdl.handle.net/10013/epic.19515

A correct interpretation of climatic records from deep ice cores requires a thorough assessment of the ice-dynamical evolution around the drill site. This is necessary to determine the history of such crucial parameters as surface elevation, flow pattern, strain rates, origin of the ice, and others, over the total period covered by the ice core. We focus on the EPICA drill site in Dronning Maud Land, and have applied a three-dimensional thermomechanical ice-sheet model of the Antarctic ice sheet nested with a detailed higher-order ice-flow model for the area around the drill site. The large-scale model is based on the shallow ice approximation, considers coupling with an ice shelf and a variable grounding-line, and is implemented on a 20 km grid. The local model includes all stress gradients in the force balance and therefore enables to reconstruct the flow history around the bore hole in much greater detail. All prognostic calculations take place within the large-scale model. Deviations from a reference state are then superimposed and interpolated on a fine 2.5 km grid for input to the fine-scale model. The local model receives boundary conditions from the large-scale model at lateral boundaries through a transition zone to eliminate the effects of different spatial resolution, but the local model does not couple back to the 3-D model. The nested model is run through the last 4 glacial cycles. For this study, we have made use of the most up-to-date ice-thickness and accumulation data collected within the framework of the various EPICA DML pre-site surveys. The presentation will focus on the methodology of the model nesting and discuss all results relevant to the interpretation of the ice-core records, including a tentative age-depth relation.