What determines the maximum sea ice extent in the Sea of Okhotsk? Importance of ocean thermal condition from the Pacific

• Published in: Journal of Geophysical Research
• Main Authors: Nakanowatari, Takuya, Ohshima, Kay I, Nagai, Sachiko
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union
• Subjects: 450; Okhotsk; Pacific; okhotsk sea; Sea ice
• Online Access: http://hdl.handle.net/2115/45754; https://doi.org/10.1029/2009JC006070

Previous studies suggested that the interannual variability of the maximum sea ice extent (MSIE) in the Sea of Okhotsk is not explained only by atmospheric conditions. In this study, we examined the effect of the ocean thermal condition on the determination of the MSIE based on observational data. We found that the MSIE is highly correlated with the sea surface temperature (SST) and ocean temperature around the East Kamchatska Current (EKC) in the Pacific in late autumn (November–December). The significant relationship between the MSIE and the SST cannot be fully explained by prevailing atmospheric variabilities. Considering that the inflow of EKC water to the Okhotsk Sea is strengthened in winter, advection of anomalous ocean temperature likely influences the MSIE. A multiple regression model constructed as a function of SST in the EKC and the air temperature at 850 hPa over the upwind region of the Okhotsk Sea in late autumn, which is another determinant factor for the MSIE, significantly improves the prediction skill for the MSIE: 70% of the variance of MSIE can be predicted at the stage of 2 to 3 months before the MSIE season. The SST in the EKC and the upwind air temperature are likely to control the sea ice extent in the northeastern and center to southern parts of the Okhotsk Sea, respectively.