최근 동해 온난화에 대한 동해 통과류의 영향 가능성

Abstract

A distinguished feature of the East Sea is the upper layer flow through the three major straits connected to the Pacific Ocean. Generally, East Sea Throughflow (EST) supplies the warm water through the Korea Strait and drains relatively cold water through the Tsugaru and the Soya Straits. The prominent long-term change of the East Sea is the deep water warming and the depletion of oxygen in the deep layer during the last 40 years. The cause of this phenomena explained mainly by the slow down of the deep convection in the northern region influenced by the global warming. In this study, the role of the EST transport variability on the East Sea warming has been investigated. To simplify the influence of the EST transport change, East Sea response of the extreme transport cases are compared using a numerical experiment using a three-dimensional regional model. Though the throughflow confined in the upper layer, it is interesting to note that the EST can affect on the meridional overturning strength by way of changing the heat transport amount to the convection favorable region. To understand long-term EST transport variability, monthly mean EST transport time series extracted from the Simple Ocean Data Assimilation (SODA) data during the period of 1958 to 2001. It shows that winter time transport anomaly seems to have overall increasing trend with PDO (Pacific Decadal Oscillation) like fluctuation. It is notable that the recent winter EST transport seems to be increased and it might be related with recent East Sea warming. The relation between the EST transport variability and local/remote wind stress variability is also discussed.