6. Sea Ice Thermodynamics

This chapter describe the physics of the sea ice formulation beginning with basic assumptions and followed by a description of the fundamental equations, various parameterization, and numerical approximations. The philosophy behind the design of the sea ice formulation of CAM2 is to use the same physics, where possible, as in the sea ice model within CCSM, which is known as CSIM for community sea ice model. In the absence of an ocean model, uncoupled simulations with CAM2 require sea ice thickness and concentration to be specified. Hence the primary function of the sea ice formulation in CAM2 is to compute surface fluxes. The new sea ice formulation in CAM2 uses parameterizations from CSIM for predicting snow depth, brine pockets, internal shortwave radiative transfer, surface albedo, ice-atmosphere drag, and surface exchange fluxes. The full CSIM is described in detail in an NCAR technical note by Briegleb et al. [2002]. The pieces of CSIM that are also used in uncoupled simulations with CAM2 are described here.