Michiel Helsen
Utrecht University, The Netherlands

Simulating Holocene Greenland ice sheet retreat in an ice sheet - earth system model framework

Time and place
Tuesday 20 October 2015, 11.15
Room C609, Arrhenius Laboratory, 6th floor

The earth system model EC-Earth is a valuable tool to calculate effects of greenhouse gas (GHG) scenarios on various components of the climate system. We aim to couple a thermomechanical ice sheet model to EC-Earth to not only quantify effects of GHG scenarios on ice mass changes, but also to take into account the effects of geometrical changes of the ice sheet on the climate system. Preliminary steps towards a coupled model are undertaken.

Here we use a LGM simulation of EC-Earth to initialize a Greenland ice sheet model, as a starting point for a simulation of the evolution of the Greenland ice sheet through the Holocene. Geological evidence of ice sheet extent is used to constrain the size of the LGM ice sheet. An energy balance approach is used to calculate the surface mass balance (SMB) over the ice sheet, to translate atmospheric fields to a realistic climate forcing for the ice sheet within EC-Earth. First results point out that the SMB forcing from EC-Earth underestimates ablation rates, which hampers a realistic simulation of Holocene retreat. In addition, a strong negative mass balance forcing from sub-shelf melting is needed to reproduce Holocene ice sheet retreat rates.