Generally speaking, the Phase-1 and Phase-2 forecasts at the end of the month-long integrations agree well with the CFSv2 initial conditions at the beginning of the next month, indicating a very good forecast for the end of the month. The major exceptions are in the summer seasons of both hemispheres, when excessive melting occurs. Follow-up diagnostics indicated that basal melting, caused by warm SSTs, was the cause of the excessive melting.

When the SST from CFSv2 forcing was substituted with SST freely evolving from the CICE internal mixed-layer ocean model, basal melting was reduced and prediction of ice extent at the end of summer was substantially improved. For more details, see the CICE final report.