HR: 0800h
AN: C51A-0095    [Abstracts]
TI: Calving Dynamics in an Ice-Stream/Ice-Shelf Model: Are Basal and Lateral Drag Stabilizing?
AU: * Dupont, T K
EM: tdupont@uci.edu
AF: Dept. of Earth System Science, University of California 3226 Croul Hall, MC 3100, Irvine, CA 92697, United States
AU: Alley, R B
EM: ralley@geosc.psu.edu
AF: Dept. of Geosciences and EESI, Pennsylvania State University 517 Deike Building, University Park, PA 16802, United States
AU: Horgan, H
EM: hhorgan@geosc.psu.edu
AF: Dept. of Geosciences and EESI, Pennsylvania State University 517 Deike Building, University Park, PA 16802, United States
AU: Parizek, B R
EM: hhorgan@geosc.psu.edu
AF: The Pennsylvania State University, 181 Smeal Building College Place, DuBois, PA 15801, United States
AU: Joughin, I
EM: ian@apl.washington.edu
AF: Polar Science Center, APL, University of Washington 1013 NE 40th Street, Seattle, WA 98105, United States
AB: Predicting the contributions of ice sheet dynamics to sea-level variations requires an understanding of the dynamics of ice-stream/ice-shelf systems. The behavior if ice shelves is particularly important given their ability to buttress the outflow of ice streams. This buttressing derives from frictional drag on the sides and areas of local grounding. Ice-shelf buttressing can be modified by changing the extent of the shelf, as shown most dramatically by the accelerations of glaciers feeding the collapsed portion of the Larsen B ice shelf (Rignot and others, 2004; Scambos and others, 2004). This leads directly to the consideration of iceberg calving, as the kinematic balance of calving and outward velocity at the ice front govern the migration of the ice front through time. In this work we apply an empirically derived calving rule to ice-shelf/ice-stream dynamics. The calving rule relates the rate of calving to the square root of the longitudinal strain rate. The shelf/stream model couples dynamic mass balance and stress equilibrium component models for a depth and width-integrated stream/shelf system. The ice front dynamically adjusts according to the difference between the ice-front velocity and the calving rate. Preliminary results indicate that an ice shelf with no lateral or basal drag is unstable with respect to the ice-front position. Here use the model to examine the ability of drag to stabilize the ice-front position, as well as the response of a stream/shelf system to perturbations of this drag.
DE: 0700 CRYOSPHERE (4540)
DE: 0726 Ice sheets
DE: 0728 Ice shelves
DE: 0798 Modeling
DE: 1621 Cryospheric change (0776)
SC: Cryosphere [C]
MN: 2007 Fall Meeting