Response of Temperature to Successive Typhoons in the South China Sea

Typhoons are serious natural disasters in coastal areas. During the summer of 2011, successive typhoons Nesat and Nalgae appeared in the South China Sea, providing a unique opportunity for us to study the response of the upper ocean to successive typhoons. We comprehensively use satellite data and C...

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Main Authors: Shuzong Han, Mingjie Wang, Bo Peng
Format: Article
Language:English
Published: MDPI AG 2022-08-01
Series:Journal of Marine Science and Engineering
Subjects:
Online Access:https://www.mdpi.com/2077-1312/10/8/1157
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author Shuzong Han
Mingjie Wang
Bo Peng
author_facet Shuzong Han
Mingjie Wang
Bo Peng
author_sort Shuzong Han
collection DOAJ
description Typhoons are serious natural disasters in coastal areas. During the summer of 2011, successive typhoons Nesat and Nalgae appeared in the South China Sea, providing a unique opportunity for us to study the response of the upper ocean to successive typhoons. We comprehensively use satellite data and COAWST model data to explore the effects of successive typhoons on the temperature structure of the South China Sea. Nesat caused the sea surface temperature to decrease by up to 4.4 °C on the right side of the typhoon path, and the ensuing Nalgae caused the temperature to decrease by up to 2.2 °C. Because Nesat had already cooled the ocean, the response to Nalgae was more to the left of the track than one would normally expect. The upwelling dominates the change in subsurface temperature. Based on the increase caused by Nesat, the isotherm was further raised by Nalgae. The isotherm rising amplitude is larger in the upper and deeper layer and is smaller in the middle layer in the depth range of 0–200 m. Heat budget analysis indicates that in the area close to the typhoon path, vertical diffusion is the main reason for the decrease in ocean surface temperature, while total advection suppresses the decrease in temperature. In the area with a larger distance from the typhoon path, vertical diffusion and total advection lead to the decrease in ocean surface temperature, and total advection will gradually contribute more to temperature change and become the dominant factor. On the right side of the typhoon track, the reduction of the contribution rate of vertical diffusion with distance from typhoon track is slower than that on the left side of the typhoon track. Whether Nesat or Nalgae, the intensity and depth of effects of vertical diffusion on the right side of typhoon path are greater than those on the left side of typhoon path, and the near-inertial periodic oscillation of local temperature change rate is more obvious. When the vertical diffusion is weak, the influence of vertical advection and horizontal advection is deeper. Moreover, the near-inertial periodic oscillation of the local temperature change occurs in lower depth after Nalgae passed through than that after Nesat. The typhoon intensity of the two typhoons shows the opposite change: the first typhoon increases, and the second typhoon weakens. Therefore, the special case of successive typhoons should be fully considered in typhoon prediction to improve accuracy.
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spelling doaj.art-36ff4e79d01a49b2975d6ea8606219712023-12-03T13:54:42ZengMDPI AGJournal of Marine Science and Engineering2077-13122022-08-01108115710.3390/jmse10081157Response of Temperature to Successive Typhoons in the South China SeaShuzong Han0Mingjie Wang1Bo Peng2College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, ChinaCollege of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, ChinaSchool of Ocean and Fisheries, Guangdong Eco-Engineering Polytechnic, Guangzhou 510520, ChinaTyphoons are serious natural disasters in coastal areas. During the summer of 2011, successive typhoons Nesat and Nalgae appeared in the South China Sea, providing a unique opportunity for us to study the response of the upper ocean to successive typhoons. We comprehensively use satellite data and COAWST model data to explore the effects of successive typhoons on the temperature structure of the South China Sea. Nesat caused the sea surface temperature to decrease by up to 4.4 °C on the right side of the typhoon path, and the ensuing Nalgae caused the temperature to decrease by up to 2.2 °C. Because Nesat had already cooled the ocean, the response to Nalgae was more to the left of the track than one would normally expect. The upwelling dominates the change in subsurface temperature. Based on the increase caused by Nesat, the isotherm was further raised by Nalgae. The isotherm rising amplitude is larger in the upper and deeper layer and is smaller in the middle layer in the depth range of 0–200 m. Heat budget analysis indicates that in the area close to the typhoon path, vertical diffusion is the main reason for the decrease in ocean surface temperature, while total advection suppresses the decrease in temperature. In the area with a larger distance from the typhoon path, vertical diffusion and total advection lead to the decrease in ocean surface temperature, and total advection will gradually contribute more to temperature change and become the dominant factor. On the right side of the typhoon track, the reduction of the contribution rate of vertical diffusion with distance from typhoon track is slower than that on the left side of the typhoon track. Whether Nesat or Nalgae, the intensity and depth of effects of vertical diffusion on the right side of typhoon path are greater than those on the left side of typhoon path, and the near-inertial periodic oscillation of local temperature change rate is more obvious. When the vertical diffusion is weak, the influence of vertical advection and horizontal advection is deeper. Moreover, the near-inertial periodic oscillation of the local temperature change occurs in lower depth after Nalgae passed through than that after Nesat. The typhoon intensity of the two typhoons shows the opposite change: the first typhoon increases, and the second typhoon weakens. Therefore, the special case of successive typhoons should be fully considered in typhoon prediction to improve accuracy.https://www.mdpi.com/2077-1312/10/8/1157successive typhoonsSouth China Seatemperatureheat budget
spellingShingle Shuzong Han
Mingjie Wang
Bo Peng
Response of Temperature to Successive Typhoons in the South China Sea
Journal of Marine Science and Engineering
successive typhoons
South China Sea
temperature
heat budget
title Response of Temperature to Successive Typhoons in the South China Sea
title_full Response of Temperature to Successive Typhoons in the South China Sea
title_fullStr Response of Temperature to Successive Typhoons in the South China Sea
title_full_unstemmed Response of Temperature to Successive Typhoons in the South China Sea
title_short Response of Temperature to Successive Typhoons in the South China Sea
title_sort response of temperature to successive typhoons in the south china sea
topic successive typhoons
South China Sea
temperature
heat budget
url https://www.mdpi.com/2077-1312/10/8/1157
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