Basin-wide responses of the South China Sea environment to Super Typhoon Mangkhut (2018)

Shuhong Liu; Jiagen Li; Liang Sun; Guihua Wang; Danling Tang; Ping Huang; Hong Yan; Si Gao; Chao Liu; Zhiqiu Gao; Yubin Li; Yuanjian Yang

doi:10.1016/j.scitotenv.2020.139093

Basin-wide responses of the South China Sea environment to Super Typhoon Mangkhut (2018)

Sci Total Environ. 2020 Aug 20:731:139093. doi: 10.1016/j.scitotenv.2020.139093. Epub 2020 May 4.

Authors

Shuhong Liu¹, Jiagen Li², Liang Sun³, Guihua Wang⁴, Danling Tang⁵, Ping Huang⁶, Hong Yan⁷, Si Gao⁸, Chao Liu⁹, Zhiqiu Gao⁹, Yubin Li⁹, Yuanjian Yang¹⁰

Affiliations

¹ School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, China; Guangdong Key Laboratory of Ocean Remote Sensing, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
² School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China.
³ School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China. Electronic address: sunl@ustc.edu.cn.
⁴ Department of Atmospheric and Oceanic Sciences, Fudan University, Shanghai, China.
⁵ Guangdong Key Laboratory of Ocean Remote Sensing, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
⁶ Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
⁷ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
⁸ School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
⁹ School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, China.
¹⁰ School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, China; Guangdong Key Laboratory of Ocean Remote Sensing, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Electronic address: yyj1985@nuist.edu.cn.

PMID: 32416350
DOI: 10.1016/j.scitotenv.2020.139093

Abstract

Relative to the open Northwest Pacific, the basin-scale South China Sea (SCS) is smaller and semi-enclosed, and the impacts of frequent super typhoons on the entire SCS basin have yet to be fully understood. Using multi-satellite observations and reanalysis data, this study explored biophysical responses of the upper ocean of the SCS induced by a typical super typhoon, Mangkhut (2018), and their regional differences with potential mechanisms. There were three different significant-response regions in the whole SCS, as follows: (1) In the ocean area around the typhoon path, strong vertical mixing, upwelling and cooling were induced, resulting in the surface chlorophyll-a (chl-a) concentration enhancing markedly (three-fold). Particularly, asymmetric distribution of typhoon rainfall induced asymmetric sea surface salinity change over along the path the nearshore. Diurnal peak of chl-a concentration increased obviously, and the daily growth rate of chl-a sped up considerably in non-shore areas after Mangkhut's passage. (2) In the Beibu Gulf (BBG), the peripheral winds of Mangkhut caused a change in direction of the sea surface flow field, transporting the high-temperature and high-salinity surface seawater from the southeastern area to the BBG. This induced dramatic increases in sea surface temperature, salinity and height, and a decrease in chl-a, in most areas of BBG. (3) In the southwest SCS, the southwest monsoon-induced eastward offshore upwelling jet was weakened by the opposite large-scale peripheral wind vector of Mangkhut and gradually disappeared, resulting in accumulation and enhancement of chl-a in the nearshore. In addition, Mangkhut peripheral winds also intensified (weakened), shifting the cold (warm) eddy to the north (south) and blocking the horizontal eastward transport belt of the high-concentration chl-a. In general, our present work sheds light on the new evidence that a supper typhoon can cause basin-wide anomalies in the SCS, which has broad implications for marine biophysical environment.

Keywords: Chlorophyll-a bloom; Multi-satellite remote sensing; Sea surface cooling; South China Sea; Super typhoon Mangkhut.