影响2018年盛夏热带气旋群发的多尺度环流特征分析
投稿时间:2019-07-01  修订日期:2019-07-17  点此下载全文
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作者单位E-mail
游立军 福建省气候中心 ylj16333@foxmail.com 
高建芸 福建省气候中心 fzgaojyun@163.com 
魏澎 南京信息工程大学 大气科学学院  
张维 福建省气候中心  
基金项目:国家重点研发计划(2018YFC1505906),国家自然基金项目(41575052)
中文摘要:本文以2018年盛夏一次典型的热带气旋群发(MTC)事件为例,分析了多尺度环流(包括大尺度环流、季节内振荡及热带波动等)对MTC的影响,并探讨了MTC群发期和间歇期整层大气垂直扰动场的差异,研究表明:(1)2018年盛夏西北太平洋经历了一次持续时间长达16天有8个TC相继生成的MTC群发期和紧接着长达19天仅1个TC生成的MTC间歇期;(2)MTC群发期越赤道气流增强,季风槽加强东伸,南海和西北太平洋上空低层辐合高层辐散的环流配置有利于TC生成;(3)夏季东亚-西北太平洋季节内振荡北传对MTC次季节变化具有显著的调制作用,MTC群发期(间歇期)南海和西北太平洋正好处于一次较强的ISO北传湿(干)位相上;(4)群发期内8个TC的生成皆与热带波动有关,其中5个同时受两种热带波动的影响,热带波动通过改变局地热动力状况为TC生成提供触发条件;(5)多尺度环流的共同影响最终导致MTC群发期和间歇期在温压扰动场配置、垂直运动扰动和比湿扰动的垂直结构特征上表现出显著的差异,扰动分析法的应用为MTC生成的延伸期预报提供了一个新的思路。
中文关键词:台风群发 多尺度振荡 热带波动 扰动分析 西北太平洋
 
Analysis of multi-scale circulation characteristics affecting the multiple tropical cyclogenesis in midsummer of 2018
Abstract:This study investigates the impact of multi-scale circulations (including large-scale circulation, intra-seasonal oscillation (ISO) and tropical waves) on the multiple tropical cyclogenesis (MTC) and discusses the deviation of vertical disturbance field of the whole atmosphere in the MTC active and inactive phases by taking a typical MTC in midsummer of 2018 as an example. The results are as follows. (1) The Western North Pacific (WNP) undergoes a 16-days MTC active phase with eight tropical cyclones (TCs) generated in sequence and a 19-days MTC inactive phase with only one TC generated in midsummer of 2018. (2) During the MTC active phase, the cross-equatorial airflow strengthens and monsoon trough extends eastward. The atmospheric circulation configuration of the low-level convergence and the upper level divergence in South China Sea (SCS) and WNP is conducive to TC formation. (3) The northward propagation of Eastern Asia and WNP ISO in summer has a significant modulation effect on the MTC sub-seasonal changes. The SCS and WNP are just in a northward wet (dry) phase of a strong ISO during the MTC active (inactive) phase. (4) The generation of the eight TCs in the MTC active phase is all related to tropical fluctuation, five of which are affected by two kinds of tropical waves at the same time. Tropical fluctuation provides the trigger conditions for the TC generation by changing local thermal and dynamic conditions. (5) The common influence of multi-scale circulation eventually leads to significant differences in the vertical structure characteristics of temperature-pressure disturbance field configuration, vertical motion disturbance and specific humidity disturbance in the MTC active and inactive phase. The application of the disturbance analysis method provides a new idea for the extended range forecast.
keywords:Multiple tropical cyclogenesis, Multi-scale oscillation, Tropical waves, Perturbation analysis,Western North Pacific
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