Projection of Changes in Future Surface Wind around Japan Using a Non-hydrostatic Regional Climate Model

Abstract

Changes of a surface wind under the future climate condition in and around Japan were investigated by using a 5-km-mesh non-hydrostatic regional climate model (NHRCM05). In the present climate, monthly mean surface wind speeds are well reproduced by NHRCM05. Additionally, the NHRCM05 reproduces the seasonal change of mean surface wind speeds fairly well: the wind during the cold season is calculated to be stronger than that in the warm season.
Under the future climate, monthly mean surface wind speeds show little change. In the warm season, according to a 20-km-mesh atmospheric general circulation model (AGCM20), the Pacific anticyclone is projected to weaken near Japan, and the sea level pressure over the seas around the Philippine Islands is projected to rise, so the frequency of the westerly wind is projected to increase across Japan by NHRCM05.
During the cold season, according to NHRCM05, the wind speeds around Hokkaido are projected to increase a little value due to the decrease of the sea ice in the Sea of Okhotsk. Further, the frequency of southeasterly wind is projected to increase significantly. In the future, the Monsoon Index is projected to be lower than in the present climate by AGCM20, resulting in southeasterly wind inflow to Japan.