Comment on egusphere-2022-1368

Abstract

The Los Alamos sea ice model (CICE) is being tested in standalone mode to identify biases that limit its suitability for seasonal prediction. The prescribed atmospheric forcings to drive CICE are from the NCEP Climate Forecast System Reanalysis (CFSR). A built-in mixed layer ocean model in CICE is used. Initial conditions for the sea ice and the mixed layer ocean are also from CFSR in the control experiments. The simulated sea ice extent is generally in good agreement with observations in the warm season at all lead times up to 12 months both in the Arctic and Antarctic, suggesting that CICE is able to provide useful sea ice edge information for seasonal prediction. However, the Arctic sea ice thickness forecast has a positive bias stemming from the initial conditions, and this bias often persists for more than a season, limiting the model’s seasonal forecast skill. When this bias is reduced by initializing ice thickness using the CryoSat-2 satellite observations while keeping all other initial fields unchanged in the CS2_IC experiments, both simulated ice edge and thickness improve. This confirms the important roles of sea ice thickness initialization in sea ice seasonal prediction seen in many studies.