Xiaowen Wei , Xiuping Yao , Xun Li , Zhiyan Wu , Qingchuan Wu
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The vigorous vorticity \"embryo\" provides stronger initial disturbances for MG pattern; The strong upper-level divergence and the weak deep-layer VWS provide sufficient dynamic conditions for the MC pattern; The MT pattern possess the highest SST, which supplies an ample supply of heat and moisture; The EW pattern has less beneficial conditions compared with other three patterns. The Extreme Gradient Boosting (XGBoost) method is applied to quantify the relative importance of individual factors to TD development trend. 500-hPa vorticity, 200-hPa divergence and SST are major dynamic and thermal affecting factors for TD development, the importance of which all ranked at top four in the four patterns; VWS plays an indispensable role in TD development for the MC and EW patterns; Comparely,850-hPa vorticity and vertically integrated water vapor flux are not as important as above environmental factors in deciding whether a TD develops.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101501"},"PeriodicalIF":1.9000,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Study on the genesis and development trend of tropical depressions under different large-scale backgrounds\",\"authors\":\"Xiaowen Wei , Xiuping Yao , Xun Li , Zhiyan Wu , Qingchuan Wu\",\"doi\":\"10.1016/j.dynatmoce.2024.101501\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Based on self-organizing maps (SOM), large-scale backgrounds associated with tropical depression (TD) genesis over the western North Pacific (WNP) in 1949–2021 are classified into four circulation patterns, monsoon gyre (MG) pattern, monsoon confluence (MC) pattern, monsoon trough (MT) pattern and easterly wave (EW) pattern. 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引用次数: 0
摘要
基于自组织模式图(SOM),将1949-2021年北太平洋西部热带低压生成的大尺度背景划分为四种环流模式,即季风回旋(MG)模式、季风汇合(MC)模式、季风槽(MT)模式和东风波(EW)模式。在 MC 模式下产生的热带气旋平均成因位置最南,发展概率最高;而在 EW 模式下出现的热带气旋平均成因位置最北,发展概率最低。在 MG、MT 和 EW 模式中形成的 TD 在 8 月份最为活跃,而在 MC 模式中,TD 生成数量在 10 月份达到高峰。在不同的环流模式中,形成 TD 的有利条件各不相同。强烈的涡度 "胚胎 "为 MG 模式提供了较强的初始扰动;强烈的高层辐合和较弱的深层 VWS 为 MC 模式提供了充足的动力条件;MT 模式拥有最高的 SST,可提供充足的热量和水汽;EW 模式与其他三种模式相比,有利条件较少。应用极端梯度提升(XGBoost)方法量化了各因素对 TD 发展趋势的相对重要性。500-hPa涡度、200-hPa辐合和SST是TD发展的主要动力和热力影响因子,其重要性在四种模式中均排在前四位;VWS对MC和EW模式的TD发展起着不可或缺的作用;相比之下,850-hPa涡度和垂直一体化水汽通量在决定TD是否发展方面的重要性不如上述环境因子。
Study on the genesis and development trend of tropical depressions under different large-scale backgrounds
Based on self-organizing maps (SOM), large-scale backgrounds associated with tropical depression (TD) genesis over the western North Pacific (WNP) in 1949–2021 are classified into four circulation patterns, monsoon gyre (MG) pattern, monsoon confluence (MC) pattern, monsoon trough (MT) pattern and easterly wave (EW) pattern. TDs generated in the MC pattern has the southernmost average genesis location and the highest development probability, while TDs occurred in the EW pattern are averagely located northernmost and their probability of development is the lowest. TDs formed in the MG, MT and EW patterns are most active in August, whereas in the MC pattern, TD genesis number peaks in October. Advantageous conditions for TD genesis vary in different circulation patterns. The vigorous vorticity "embryo" provides stronger initial disturbances for MG pattern; The strong upper-level divergence and the weak deep-layer VWS provide sufficient dynamic conditions for the MC pattern; The MT pattern possess the highest SST, which supplies an ample supply of heat and moisture; The EW pattern has less beneficial conditions compared with other three patterns. The Extreme Gradient Boosting (XGBoost) method is applied to quantify the relative importance of individual factors to TD development trend. 500-hPa vorticity, 200-hPa divergence and SST are major dynamic and thermal affecting factors for TD development, the importance of which all ranked at top four in the four patterns; VWS plays an indispensable role in TD development for the MC and EW patterns; Comparely,850-hPa vorticity and vertically integrated water vapor flux are not as important as above environmental factors in deciding whether a TD develops.
期刊介绍:
Dynamics of Atmospheres and Oceans is an international journal for research related to the dynamical and physical processes governing atmospheres, oceans and climate.
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