Unusual coastal ocean cooling in the northern South China Sea by a katabatic cold jet associated with Typhoon Mujigea(2015)

作     者：Yuxin Shi Lingling Xie Quanan Zheng Shuwen Zhang Mingming Li Junyi Li 

作者机构：Guangdong Key Laboratory of Coastal Ocean Variation and Disaster Prediction Guangdong Ocean University Department of Atmospheric and Oceanic Science University of Maryland 

出 版 物：《Acta Oceanologica Sinica》 (海洋学报（英文版）)

年 卷 期：2019年第38卷第5期

页      面：62-75页

核心收录：

学科分类：07[理学] 

基　　金：The National Natural Science Foundation of China under contract Nos 41776034,41476009 and41706025 the GASI Project under contract Nos GASI-IPOVAI-01-02 and GASI-02-SCS-YGST2-02 the Natural Key Research and Development Program of China under contract No 2016YFC1401403 the Foundation of Guangdong Province for Outstanding Young Teachers in University under contract No.YQ201588 

主　　题：Typhoon Mujigea(2015) second-round cooling katabatic cold jet South China Sea westerly wind front 

摘      要：This study deals with a unusual cooling event after Typhoon Mujigea passed over the northern South China Sea(SCS) in October 2015. We analyze the satellite sea surface temperature(SST) time series from October 3 to 18,2015 and find that the cooling process in the coastal ocean had two different stages. The first stage occurred immediately after typhoon passage on October 3, and reached a maximum SST drop of –2℃ on October 7 as the usual cold wake after typhoon. The second stage or the unusual extended cooling event occurred after 7d of the typhoon passage, and lasted for 5d from October 10 to 15. The maximum SST cooling was –4℃ and occurred after 12d of typhoon passage. The mechanism analysis results indicate that after landing and moving northwestward to the Yunnan-Guizhou Plateau(YGP), Typhoon Mujigea(2015) met the westerly wind front on October 5. The lowpressure and positive-vorticity disturbances to the front triggered meridional air flow and low-pressure trough,thus induced a katabatic cold jet downward from the Qinghai-Tibet Plateau(QTP) passing through the YGP to the northwestern SCS. The second cooling reached the maximum SST drop 4d later after the maximum air temperature drop of –9℃ on October 11. The simultaneous air temperature and SST observations at three coastal stations reveal that it is this katabatic cold jet intrusion to lead the unusual SST cooling event.