Arctic sea ice thickness (SIT) reforecasts on subseasonal time scales from European Centre for Medium-Range Weather Forecasts (ECMWF) have been evaluated based on a newly developed SIT reanalysis, the Combined Model and Satellite Thickness (CMST). Compared with the persistence forecast, the ECMWF shows a promising predictive capability during winter and summer for lead days longer than 30. However, ECMWF reforecasts overestimate SIT in the Beaufort Sea while underestimate SIT in the Central Arctic, and similar conditions can also be found in the initial state. Further exploration reveals that the overestimation of ECWMF in the Beaufort Sea is monthly dependent, with its disappearance in August and September, whereas the underestimation in the Central Arctic can be seen all the year round. Our results suggest that SIT initialization in ECMWF needs to be improved significantly for better predictive skill.
 

sea ice modeling, sea ice forecast