Asynchronously coupling the cryosphere and atmosphere in an energy-balance climate model

Abstract

A major component of the climate system on the 10 000-100 000 year time-scales is continental ice sheets, yet many of the mechanisms involved in the land-sea-ice processes that affect the ice sheets are poorly understood. In order to examine these processes in more detail, we have developed a coupled energy balance climate-thermodynamic sea-ice—continental-ice-sheet model (CCSLI model). This model includes a hydrologic cycle, a detailed surface energy and mass balance, a thermodynamic sea-ice model, and a zonally averaged dynamic ice-flow model with bedrock depression.Because of the variety of space and time-scales inherent in such a model, we have asynchronously coupled the land—ice model to the other components of the model. In this paper the asynchronous coupling is described and sensitivity studies are presented that determine the values of the asynchronous coupling parameters. Model simulations using these values allow the model to run nearly ten times faster with minimal changes in the final state of the ice sheet.