Diverse Responses of Polar Mesocyclones Genesis Attributable to Orographic Forcing

Polar mesocyclones (PMCs) are mesoscale, maritime cyclones that occur around the high latitudes in the cold seasons. Over the northern Sea of Japan, PMC frequently occurs with cold air outbreaks from the east of the Eurasian Continent. In this study, effects of the mountains on the eastern end of the Eurasian Continent (Sikhote-Alin mountain range) on the PMCs genesis were examined by 36-years long-term numerical experiments. The sensitivity experiment, in which the Sikhote-Alin mountain range is removed, shows that the number of PMC genesis decreases and the duration between PMCs genesis and landfall becomes shorter compared with realistic experiment. These differences arise only in the southern part of the sea. This result suggests that the effect of the orographic forcing on PMC's behavior varies with the location of the PMCs genesis.