기후변화로 예측된 바람장에 반응하여 나타나는 동아시아지역해 수송량 변화에 대한 수치 실험

Abstract

As an approach to investigate the regional assesment of the East Asian Marginal Seas (EAMS) response to the climate change, we have carried out a simple experiment on the volume transport variability of the EAMS forced by the two kinds of wind stresses. One is the present wind stresses reproduced by the 20 year (1981 - 2000) averaged GFDL (Geophysical Fluid Dynamic Laboratory, U. S.) Climate Model version 2.1 (CM 2.1) and the other is the average wind stresses over the period of year 2081 - 2100 predicted by the same model under the assumption of the IPCC (Intergovernmental Panel on Climate Change) A1B scenario. A two-dimensional globally variable grid model based on the POM (Princeton Ocean Model) with the finest mesh around the EAMS has been used for this experiment. The overall (annual mean) volume transports in the EAMS seem to decrease about 10 - 30% because of the weakening of the subtropic and subpolar gyre in the northern Pacific. This weakening of gyre strength is related with the decrease of the negative and positive wind stress curl, respectively. Nevertheless, it is interesting that the East Sea Throughflow (EST) transport is not much changed (actually it increased very slightly, about 0.03 Sv). Since the EST supplies warm water through the Korea Strait and drains rather cooled water out of the East Sea through the Tsugaru and Soya Straits, if other things are not changed, the increased EST might contribute to warm the East Sea in the future. It is noteworthy that the seasonal responses of the EAMS to the future wind stresses are very different. Most of the volume transports calculated at the several sections decrease in summer while they increase in winter. The possible explanation of this seasonal inconsistency has been sought in relation with the monsoon strength change as well as the local and remote wind stress curl variations.