HR: 14:40h
AN: C43A-05    [Abstracts]
TI: How Sensitive is a Greenland Ice Sheet Model?
AU: * Adalgeirsdottir, G
EM: gua@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 2100, Denmark
AU: Stendel, M
EM: mas@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 2100, Denmark
AU: Christensen, J H
EM: jhc@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 2100, Denmark
AU: Drews, M
EM: mad@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 2100, Denmark
AU: Fox Maule, C
EM: cam@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 2100, Denmark
AB: No model is better than its physical ingredients, approximations, parameterizations, boundary and initial conditions. This is particularly true for models of the Greenland Ice Sheet (GrIS). There is an urgent need to determine the predictability of models for the response of GrIS to rising temperatures and the amount of freshwater flux that can be expected into the ocean. We explore the sensitivity of a GrIS model to various model components; the resolution, the modeled climate (surface boundary condition), geothermal heat flux beneath the ice sheet and a few warming scenarios. Simulations are done with the polythermal ice sheet model SICOPOLIS. Model time for all simulations is from 250 kyr BP until today. Initial conditions are provided by spin-up simulations from 422 kyr BP until 250 kyr BP. Climate forcing is based on the GRIP temperature history from the δ¹⁸O record. Surface melting is parameterized by a degree-day method. First experiments indicate strong dependency on how the present climate and the geothermal heat flux are defined. Generally the periphery is controlled by the surface boundary condition and the central ice thickness by the geothermal heat flux.
DE: 0726 Ice sheets
DE: 0774 Dynamics
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting