the 22nd Pacific−Asian Marginal Seas meeting (PAMS)

The southern Sea of Okhotsk off Hokkaido is the most southern region where sea ice can reach in the northern hemisphere. The sea ice in this region has therefore been considered to be sensitive to the global warming. In this article, we describe results of numerical experiments evaluating the variability of sea ice in 2050 and 2090 off the Hokkaido Okhotsk coast. An ocean-sea ice model, covering the seas surrounding Hokkaido (with a grid of 1/50°), is nested to a parent model that covers the entire Sea of Okhotsk (with a grid of 1/10°) to evaluate the future sea ice variability. This ocean-sea ice model is forced by future atmospheric conditions that are produced by adding the “difference between the future climate and the 2000 climate”, retrieved from the Coupled Model Intercomparison Project phase 6 (CMIP6) model ensembles, to the “present” atmospheric reanalysis (1993-2017). The ocean-sea ice model predicted that the sea ice duration (SID) will be reduced to 1/3 in 2050 compared to the present sea ice duration even under a low greenhouse gas emission scenario, but nevertheless, the SID maintains this level toward the end of the 21^st century. On the other hand, under the high greenhouse gas emission scenario, sea ice almost disappears from the coast of Hokkaido by the end of 21^st century. It is evaluated that the number of years when sea ice arrives at the Hokkaido coast will be halved if the wintertime air temperature rise over Hokkaido exceeds 3.5℃ compared to the present climate.
 

sea ice prediction,CMIP6,Hokkaido Okhotsk coast