, ,
, ,
, ,
In order to meet the urgent need of sub-seasonal to seasonal forecast NCEP started their 9-month seasonal forecasts from 2012 using Climate Forecast System version 2 (CFSv2). In this study, we examined the predictability of Arctic sea ice and atmospheric forcing fields produced by CFSv2. What we found is that the extra large sea ice cover at the end of summer are actually caused by the relative large cold temperature biases in the same region. The predicted atmospheric forcing fields are evaluated against several reanalysis products including the European Center for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim), NASA the Modern Era Retrospective-analysis for Research and Applications, version 2 (MERRA2), NCE-CFSR, and NCEP/NCAR-Reanaysis (R1). While there are discrepancies among the reanalysis products, we do find that some are better performed than the others on selected fields. The variables we investigated are those regional or stand-alone ocean-ice models will take as their atmospheric forcings. The quality of these variables is therefore has direct impact on the regional or stand-alone ocean-ice model simulation results. Further analyses reveal that biases in turbulent heat fluxes are believed to be the main factor leading to the sea ice forecast biases. The forecast bias in the surface short wave and long wave radiative forcing can mainly be attributed to the cloud cover uncertainty in the Arctic.