Sensitivity of the Antarctic sea-ice distribution to oceanic heat flux in a coupled atmosphere-sea-ice model

Abstract

A coupled atmosphere-sea-ice model is used to study the sensitivity of the Antarctic sea-ice distribution to oceanic heat flux (OHF). Remote sensing of sea ice from microwave radiometers provides data on ice extent and ice concentration. The ice-thickness data used are from ship-based observations. Our simulations suggest that OHF values of 0-5 Wm2 will cause sea ice to be too thick in the model. A value of 20-25 Wm2 throughout the year causes sea ice to be too thin in the model. The model results indicate that a seasonally varying OHF is required to match the modelled thickness with observations. Values of 5-30 Wm2, with an annual mean of 10-15 Wm2, give a reasonable distribution of sea-ice thickness. This agrees with the limited observations of OHF available for the Antarctic. The model results also indicate that the OHF should be varied spatially. When a seasonally and spatially variable OHF is applied to the coupled atmosphere-sea-ice model a still better simulation of the sea-ice distribution is obtained. Our results also suggest that the role of ice advection is very important in the determination of the sea-ice distribution, and it can be quantified by the model.