ISMIP - POLICE: a new intercomparison exercise to assess model uncertainties in polar ice sheet simulations under future climatic warming conditions.

1. Aims of POLICE

POLICE (Polar Ice Sheet Models) aims at comparing the mass-balance and ice-dynamic components of the current generation of Antarctic and Greenland ice sheet models under conditions of future climatic warming.

Future model projections are characterised by large uncertainties. These derive to a large extent from the wide range of climate changes predicted by available AOGCMs because of greenhouse gas emission scenarios and climate sensitivities of individual models.

Additional uncertainty is however introduced by the way these climate changes are used in glaciological models to force changes in ice-sheet mass-balance (snow accumulation, melt water runoff, basal melting below ice shelves), and by the way these models deal with ice-dynamics.

2. Type of experiments

The proposed experiments all consider the same climate and ocean forcing (temperature, precipitation) but do not impose any other constraints on model parameters and model physics. The exercise will therefore focus on questions of ice-dynamic changes versus static mass-balance changes, and on the various treatments for prescribing mass-balance changes in contemporary models of the polar ice sheets. Intercomparison of individual model formulations (physics and numerics) is not intended here as this was already the subject of the EISMINT intercomparison activities.

3. Participating models

ISMIP-POLICE seeks participants running 2D or 3D plan-form time-dependent ice-dynamic models applied to all or parts of the Greenland and Antarctic ice sheets.

Interested participants in this series of model tests are asked to first register with Philippe Huybrechts (phuybrec@vub.ac.be)

This announcement will soon be followed by all documents and datasets describing the experimental setup.