2002b), Ice-flow characteristics over a rough bedrock: Implications for ice-core interpretation, Polar Meteorol

• Main Author: Frank Pattyn
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Dronning Maud Land; Antarc*; Antarctica; EPICA; ice core; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.723.5027; http://homepages.ulb.ac.be/%7Efpattyn/papers/Pattyn2002_PMG.pdf

Recent observations in western Dronning Maud Land, Antarctica, point to a relatively high bedrock roughness in the area of the future EPICA drilling site. It is commonly accepted that such a roughness does not favor the interpretation of deep ice cores as basal ice-sheet interactions might disturb the bottom ice layers. The present study aims at examining the ice-flow characteristics over a strongly undulating bed and investigates its influence on age-depth profiles in the ice sheet. For this purpose a high-resolution time-dependent two-dimensional flowline model was developed (hor-izontal gridsize 1 km), taking into account all relevant stresses at such a small scale. The model is solved on a fixed finite-difference grid, and compared with a similar model, solving the velocity field accord-ing to the shallow-ice approximation. The analysis is presented for sinusoidal bedrock undulations with amplitude-to-wavelength ratio comparable to those observed by radio-echo sounding (STEINHAGE et al., 1999). Calculations are performed over a period of 300 ka. Results demonstrate that the influence of a high bed roughness on the age-depth profiles is not only confined close to the bed, but near the surface as well, which might affect the interpretation of shallow ice cores. Ice-flow characteristics over a rough bedrock 1