Fig. 2: Initial SIC on August 1st for different assimilation experiments and their differences from observations (2004–2023 average).

The spatial distribution of mean SIC from (a) the SIC-only experiment (assimilating SIC alone), (b) the SIC-SIT experiment (assimilating both SIC and SIT). The mean SIC differences: (c) SIC-only experiment minus observations, (d) SIC-SIT experiment minus observations. Only the differences that exceed the 95% confidence level using a two-tailed Student’s t-test are presented, with the MAE indicated in the bottom left corner.