Thermodynamic Ice Model Simulations of SHEBA: Initialization and Albedo Sensitivities

A goal of the Surface Heat Budget of the Arctic (SHEBA) program is to understand the processes controlling ice-albedo feedback in the Arctic and to use this understanding to improve climate models. One step in this process is to perform experiments with thermodynamic sea ice models that represent either a one-dimensional column of ice or a single cell that includes a distribution of ice thickness. This research will use the new sea ice component implemented in both the NCAR Community Climate System Model (CCSM) and the Parallel Climate Model (PCM), which are global, coupled atmosphere-ocean-sea ice models used for climate-change simulations. The new CCSM ice model includes: energy- and mass-conserving thermodynamics, a multiple-category ice thickness distribution model, and elastic-viscous-plastic ice dynamics. The thermodynamics includes four temperature layers, and temperature- and salinity-dependent thermal properties in the sea ice, with a fixed salinity profile.

Thermodynamic ice model simulations with the CCSM sea ice model will be presented for the SHEBA year using a variety of initial conditions and albedo parameterizations. The impact of using in situ observed ice temperatures versus idealized temperatures to initialize the model will be shown. Simulations using observed ice albedo and the model's albedo parameterization will be compared. A modified ice albedo parameterization for the CCSM ice model will be presented that improves the representation of snow cover and ponded areas. The development of improved ice albedo parameterizations and ice model processes (like melt pond formation) will continue with the ongoing synthesis of SHEBA data sets.