Ice–ocean boundary conditions for coupled models

Coupled general circulation models are becoming more sophisticated, particularly with respect to the sea ice component and the increasing use of free surface formulations in the ocean. It is therefore timely to revisit the boundary conditions at the sea ice–ocean interface to ensure that (a) mass and energy are conserved, (b) the physics represented is as realistic as possible, and (c) numerical instabilities are avoided. We present here an overview of recent practice from the GISS, NCAR CCSM2.0 and MPI Hamburg coupled models. A new formulation of the basal sea ice fluxes, discussions of lateral melt and snow–ice formation, coupling strategies for the sea ice dynamics component, and interactions with dynamic free surfaces are presented.