태풍에 의한 해수면 냉각에 있어 양자강 저염수의 영향

Abstract

The impact of the Changjiang Diluted Water (CDW) on typhoon (TY) intensity was studied using the Princeton Ocean Model (POM). The numerical experiments consists of three part :ⅰ) the stationary typhoon experiment for the investigating effect of CDW on the cooling process, ⅱ) the moving tyhpoon experiment for the finding role of translation speed on the CDW effect, ⅲ) the ocean stability experiment for the investigating effect of ocean stability on the cooling. The results of the experiments suggest that the CDW can prevent the sea surface temperature (SST) cooling during the typhoon passage in the East China Sea (ECS) and affect the typhoon intensity. This was accomplished by the enhanced stratification in halocline due to the surface low salinity water originated from the CDW. The strong stratification prevented vertical transport of momentum to downward, and disturbed deep mixing, leading to the reduction of remains at the upper layer sea surface cooling. The momentum which could not transfer to deeper layer due to the strong stratification, produced stronger surface currents. The enhanced surface currents generated strong divergence, and resultantly strong upwelling. This accelerated the surface cooling process. Therefore, the effects of the enhanced stratification due to the CDW play both positive and negative roles on the sea surface cooling. And these two process depended on the storm translation speed (STS). For the fast (slow)-moving typhoon, upwelling process was unimportant (important), so the CDW contributed to less (more) surface cooling. However, when the STS was about 6m/s on average in this region, the CDW played a overall positive role on the typhoon intensity changed by the reduction of cooling.