고해상도 모델을 이용한 쓰시마 난류의 기원과 동중국해순환 연구

Abstract

Using a high resolution global ocean circulation model results, the origin of the Tsushima Warm Current and related East China Sea Circulation have been investigated. The transport of the simulated Taiwan Warm Current is comparable to the observations, but that of the Tsushima Warm Current is about 30 % less that the observations. Even though we take into account the weak Tsushima Warm Current, the persistence of the Taiwan-Tsushima Current System shows that the Taiwan Warm Current is responsible for more than half of the observed Tsushima Current. North of Taiwan and west of Kyushu, the current system encounters with the Kuroshio Branch Currents, and if they are not differentiated properly the strength of the branch currents, and subsequently the strength of the Kuroshio intrusion could be overestimated. Of course, we need high resolution models or observation to discern the currents. Mass balance estimations conducted around those areas show that west of Kyushu the branch current is strong between September and February, and north of Taiwan between June and November. Their annual mean transports of the branch currents are 0.32 Sv west of Kyushu and 0.22 Sv north of Taiwan. Since the simulated Tsushima Warm Current is weaker than the observation, the strength of the intrusion is weaker than the reality. A linear relation between the transport of the Tsushima Warm Current and the sea level difference between the Korea/Tsushima Strait and the Tsugaru/Soya Straits is found, and we can conclude that the sea level difference is the main driving force of the current.