A technique for generating consistent ice sheet initial conditions for coupled ice sheet/climate models
A transient technique for generating ice sheet preindustrial initial conditions for long-term coupled ice sheet/climate model simulations is developed and demonstrated over the Greenland ice sheet using the Community Earth System Model (CESM). End-member paleoclimate simulations of the last glacial...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2014-06-01
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Series: | Geoscientific Model Development |
Online Access: | http://www.geosci-model-dev.net/7/1183/2014/gmd-7-1183-2014.pdf |
Summary: | A transient technique for generating ice sheet preindustrial initial
conditions for long-term coupled ice sheet/climate model simulations is
developed and demonstrated over the Greenland ice sheet using the Community
Earth System Model (CESM). End-member paleoclimate simulations of the last
glacial maximum, mid-Holocene optimum and the preindustrial are combined
using weighting provided by ice core data time series to derive continuous
energy-balance-model-derived surface mass balance and surface temperature
fields, which are subsequently used to force a long transient ice sheet model
simulation of the last glacial cycle, ending at the preindustrial. The
procedure accounts for the evolution of climate through the last glacial
period and converges to a simulated preindustrial ice sheet that is
geometrically and thermodynamically consistent with the preindustrial CESM
state, yet contains a transient memory of past climate. The preindustrial
state generated using this technique notably improves upon the standard
equilibrium spin-up technique, relative to observations and other model
studies, although in the demonstration we present here, large biases remain
due primarily to climate model forcing biases. Ultimately, the method we
describe provides a clear template for generating initial conditions for ice
sheets within a fully coupled climate model framework that allows for
the effects of past climate history to be self-consistently included in long-term simulations of the fully coupled ice sheet/climate system. |
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ISSN: | 1991-959X 1991-9603 |