Development of a new coupled ice sheet-climate model for simulations of the Antarctic Ice Sheet under a warm climate

A major obstacle in both paleo and future simulations of the Antarctic Ice Sheet is that most studies do not include interactive ice sheets. Although this is a current area of development, most studies use stand alone climate models to force separate ice sheet models to study the potential impacts of climate changes on ice sheets; however this method ignores consequent impacts of the ice sheets on the ocean-atmosphere system, leading to simulations that may under or over estimate retreat in a warmer climate. The few model simulations that do include ice sheet-climate feedbacks disagree on the overall sign of the these feedbacks.
Here we are developing a new coupling between an established ice sheet (PSU-ISM) and climate model (HadCM3) that has been used extensively for paleoclimate applications. These models are suitable for performing multiple simulations over thousands of years. The ice sheet model output will be used to update the ice sheet in the climate model. The climate model orography and land sea mask will be modified to match that in the ice sheet model and ice sheet discharge will be added as a freshwater flux, modelled via change in salinity around the Southern Ocean. The models have been coupled offline and we are next automating this process so that simulations can be repeated over shorter timescales. This will allow the model to develop feedbacks more quickly rather than being limited to the length of the run. The model has been developed using pre-industrial idealised simulations. The main focus of the work is on reproducing the AIS response and sea level rise during the middle Miocene warm interval that matches proxy records more closely without having to add unrealistic CO2 forcing.