Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset

Abstract This study reveals the remarkable differences in the synoptic‐scale tropical waves before and after the South China Sea (SCS) summer monsoon (SCSSM) onset. Before the monsoon onset, the dominant synoptic‐scale systems around the SCS are the eastward‐propagating equatorial Kelvin waves. Afte...

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Main Authors: Peng Hu, Wen Chen, Shangfeng Chen, Jingliang Huangfu, Yulian Tang, Zhibo Li, Ming Sun, Lin Wang, Yuyun Liu
Format: Article
Language:English
Published: Wiley 2025-04-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2025GL114763
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author Peng Hu
Wen Chen
Shangfeng Chen
Jingliang Huangfu
Yulian Tang
Zhibo Li
Ming Sun
Lin Wang
Yuyun Liu
author_facet Peng Hu
Wen Chen
Shangfeng Chen
Jingliang Huangfu
Yulian Tang
Zhibo Li
Ming Sun
Lin Wang
Yuyun Liu
author_sort Peng Hu
collection DOAJ
description Abstract This study reveals the remarkable differences in the synoptic‐scale tropical waves before and after the South China Sea (SCS) summer monsoon (SCSSM) onset. Before the monsoon onset, the dominant synoptic‐scale systems around the SCS are the eastward‐propagating equatorial Kelvin waves. After the SCSSM onset, while the Kelvin waves remain largely unaltered, the transitions from mixed Rossby‐gravity waves to tropical depression (TD)‐type waves become more pronounced. Such distinctive features of the tropical waves before and after SCSSM onset are attributable to the adjustments in atmospheric mean flow. An anomalous low‐level cyclone develops around the SCS after the monsoon onset. The convergence and shear of this anomalous low‐level cyclone contribute to the barotropic energy conversion from the mean flow to the synoptic‐scale systems, which is conducive to the development of TD‐type waves and genesis of tropical cyclones.
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institution Kabale University
issn 0094-8276
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language English
publishDate 2025-04-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-d806c5f5e568430f8db6807dfd9041252025-08-20T03:39:04ZengWileyGeophysical Research Letters0094-82761944-80072025-04-01528n/an/a10.1029/2025GL114763Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon OnsetPeng Hu0Wen Chen1Shangfeng Chen2Jingliang Huangfu3Yulian Tang4Zhibo Li5Ming Sun6Lin Wang7Yuyun Liu8Yunnan International Joint Laboratory of Monsoon and Extreme Climate Disasters Yunnan University Kunming ChinaYunnan International Joint Laboratory of Monsoon and Extreme Climate Disasters Yunnan University Kunming ChinaState Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaState Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaState Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaRegional Climate Group Department of Earth Sciences University of Gothenburg Gothenburg SwedenAnhui Climate Center Anhui Meteorological Administration Hefei ChinaCenter for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaCenter for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaAbstract This study reveals the remarkable differences in the synoptic‐scale tropical waves before and after the South China Sea (SCS) summer monsoon (SCSSM) onset. Before the monsoon onset, the dominant synoptic‐scale systems around the SCS are the eastward‐propagating equatorial Kelvin waves. After the SCSSM onset, while the Kelvin waves remain largely unaltered, the transitions from mixed Rossby‐gravity waves to tropical depression (TD)‐type waves become more pronounced. Such distinctive features of the tropical waves before and after SCSSM onset are attributable to the adjustments in atmospheric mean flow. An anomalous low‐level cyclone develops around the SCS after the monsoon onset. The convergence and shear of this anomalous low‐level cyclone contribute to the barotropic energy conversion from the mean flow to the synoptic‐scale systems, which is conducive to the development of TD‐type waves and genesis of tropical cyclones.https://doi.org/10.1029/2025GL114763South China Sea summer monsoon onsettropical wavesKelvin waveMRG waveTD‐type wave
spellingShingle Peng Hu
Wen Chen
Shangfeng Chen
Jingliang Huangfu
Yulian Tang
Zhibo Li
Ming Sun
Lin Wang
Yuyun Liu
Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset
Geophysical Research Letters
South China Sea summer monsoon onset
tropical waves
Kelvin wave
MRG wave
TD‐type wave
title Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset
title_full Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset
title_fullStr Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset
title_full_unstemmed Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset
title_short Distinctive Features of Tropical Waves Before and After the South China Sea Summer Monsoon Onset
title_sort distinctive features of tropical waves before and after the south china sea summer monsoon onset
topic South China Sea summer monsoon onset
tropical waves
Kelvin wave
MRG wave
TD‐type wave
url https://doi.org/10.1029/2025GL114763
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AT jinglianghuangfu distinctivefeaturesoftropicalwavesbeforeandafterthesouthchinaseasummermonsoononset
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