Dissipation process of summer tropical easterly waves in Western North Pacific

Liping Deng, Wan Ru Huang*, Jinghua Chen, S. Y.Simon Wang


研究成果: 雜誌貢獻期刊論文同行評審


Tropical easterly waves are common features in the trade wind zones and they are important sources of tropical cyclogenesis. Despite numerous studies have analyzed the genesis and maintenance of easterly waves in the Western North Pacific, few had examined their dissipation processes. Focusing on tropical easterly waves during May-September of 1979–2017, this study shows that most of the easterly waves (∼70 %) eventually dissipate when encountering the monsoon trough and associated westerlies, while 22 % were carried northward by the monsoonal southwesterly flows and became recurving disturbances. Less than 10 % of easterly waves propagate across the South China Sea against the prevailing monsoon westerlies and into the Indochina peninsula. The vorticity budget analysis illustrates that total vortex stretching in the lower troposphere is the key factor in propelling the small number of easterly waves westward, suggesting that stronger and more convectively active easterly waves tend to move further into the developed monsoon trough. This echoes the previous observation that tropical disturbances alone have a limited probability in developing into a typhoon, for those disturbances or easterly waves almost always need to interact with the monsoon trough or a monsoon gyre, as well as other intraseasonal features to sustain the organized convection and rotation.

期刊Dynamics of Atmospheres and Oceans
出版狀態已發佈 - 2021 3月

ASJC Scopus subject areas

  • 海洋學
  • 地質學
  • 地球科學電腦
  • 大氣科學


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