A glacial systems model configured for large ensemble analysis of Antarctic deglaciation 1Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada
19 Dec 2013
2Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA, USA
*now at: C-CORE, St. John's, NL, A1B 3X5, Canada
Received: 05 March 2013 – Published in The Cryosphere Discuss.: 11 April 2013 Abstract. This article describes the Memorial University of Newfoundland/Penn State
University (MUN/PSU) glacial systems model (GSM) that has been developed
specifically for large-ensemble data-constrained analysis of past Antarctic
Ice Sheet evolution. Our approach emphasizes the introduction of a large set
of model parameters to explicitly account for the uncertainties inherent in
the modelling of such a complex system.
Revised: 01 November 2013 – Accepted: 08 November 2013 – Published: 19 December 2013
At the core of the GSM is a 3-D thermo-mechanically coupled ice sheet model
that solves both the shallow ice and shallow shelf approximations. This
enables the different stress regimes of ice sheet, ice shelves, and ice
streams to be represented. The grounding line is modelled through an
analytical sub-grid flux parameterization. To this dynamical core the
following have been added: a heavily parameterized basal drag component; a
visco-elastic isostatic adjustment solver; a diverse set of climate forcings
(to remove any reliance on any single method); tidewater and ice shelf
calving functionality; and a new physically motivated, empirically-derived
sub-ice-shelf melt (SSM) component. To assess the accuracy of the latter, we
compare predicted SSM values against a compilation of published observations.
Within parametric and observational uncertainties, computed SSM for the
present-day ice sheet is in accord with observations for all but the Filchner
The GSM has 31 ensemble parameters that are varied to account (in part) for
the uncertainty in the ice physics, the climate forcing, and the ice–ocean
interaction. We document the parameters and parametric sensitivity of the
model to motivate the choice of ensemble parameters in a quest to
approximately bound reality (within the limits of 31 parameters).
Citation: Briggs, R., Pollard, D., and Tarasov, L.: A glacial systems model configured for large ensemble analysis of Antarctic deglaciation, The Cryosphere, 7, 1949-1970, doi:10.5194/tc-7-1949-2013, 2013.