상층해양의 수온(열적)구조가 한반도의 태풍강도에 미치는 영향

Abstract

Oceanic roles in the intensity of typhoons which made landfall in the Korean peninsula (KP) are investigated using various meteorological and oceanic measurements and the best track data, focusing on exploring upper-ocean thermal conditions necessary to become the most destructive typhoons in the KP. Based on hydrographic measurements and ocean modeling results, the subsurface thermal structure (STS) along the track of the KP-landfalltyphoons reveals two distinct features: the deep subsurface warm layer regions influenced by the Kuroshio Branch Current West of Kyushu (KBCWK) and Tsushima Current (TSC) and the shallow subsurface warm layer regions influenced by the Yellow Sea Bottom Cold Water (YSBCW). Jeju Island is a border dividing two regions.Statistical analysis shows that 70-90% of the strongest 10 typhoons in the KP passed through the eastern side of Jeju Island where the warm ocean currents exist at the subsurface. On the contrary, the majority of typhoons passed over the YSBCW regions where cold water exists at the subsurface, through the western side of Jeju Island, experience a large surface temperature cooling due to the storm’s self-induced vertical mixing and upwelling, resulting in the significant decrease of the intensity. These results demonstrate that the intensity of the KP-landfall typhoons is very sensitive to the storm’s track and how the difference of the upper ocean thermal structures in small areas can affect the typhoon intensity change.