Past and Future Changes in Sea Ice in the Sea of Okhotsk: Analysis Using the Future Ocean Regional Projection Dataset

Although subject to annual fluctuations, sea ice in the Sea of Okhotsk has decreased to a maximum extent at a rate of approximately 3.4% per decade since the 1970s. Thus far, few studies have focused on projections of sea ice in the Sea of Okhotsk. This study focused on sea ice in the Sea of Okhotsk and examined its past and future characteristics using a climate projection dataset termed the Future Ocean Regional Projection dataset. Historical sea ice areas have been reported to be larger than satellite observations, and some data contain biases of approximately double the actual value. Therefore, a simple bias correction was performed based on the ratio of historical to satellite observation sea-ice areas, and the bias was corrected. Furthermore, we performed future projections using two bias-corrected scenarios (RCP2.6 and RCP8.5). Results revealed that for the future analysis period of 2006–2100, sea ice loss would be approximately 12.3 (10² km²/year) under RCP2.6 and approximately 37.3 (10² km²/year) under RCP8.5, indicating that under both scenarios, there would be almost no sea ice in the southern Sea of Okhotsk between 2071 and 2100. The results of this study provide useful information for researchers to predict sea ice in related physical fields.