북서태평양 전향 태풍의 특징과 해양반응에 관한 연구

Abstract

Typhoon is known to move with the lowest moving speed during the recurvature. Since the slow-moving typhoons experience a strong air-sea interaction mainly due to the storm's self-induced vertical mixing and upwelling, oceanic conditions prior to and during the recurvature are very important in determining the recurving typhoon intensity. This study aims to investigate characteristics of the recurving typhoon depending on the pre-existing oceanic conditions in the western North Pacific using the JTWC (Joint Typhoon Warning Center) best track and WOA 2005 (World Ocean Atlas 2005) data during 1951-2009. For this, various statistical analyses have been conducted according to the recurvature location, angle and time as well as the moving speed, ocean heat content (OHC) during the recurvature. A statistical analysis is conducted to investigate behavior of typhoon according to different OHC conditions. The results reveals that the intensity of recurving typhoons was more increased (decreased) than that of straight-moving typhoons under the high (low) OHC conditions. This implies that the recurving typhoons do more interact with ocean than the straight ones simply due to the enhanced wind forcing by recurvature. A series of numerical experiments is performed to investigate the oceanic response for the typhoons with different recurving angle and moving speed. The result shows typhoons with that small recurving angle and low moving speed produces the biggest sea surface cooling.