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卜松, 李英. 华东登陆热带气旋降水不同分布的对比分析[J]. 大气科学, 2020, 44(1): 27-38. DOI: 10.3878/j.issn.1006-9895.1906.18180
引用本文: 卜松, 李英. 华东登陆热带气旋降水不同分布的对比分析[J]. 大气科学, 2020, 44(1): 27-38. DOI: 10.3878/j.issn.1006-9895.1906.18180
Comparative Analysis of Precipitation Distributions of Tropical Cyclones Making Landfall in East China[J]. Chinese Journal of Atmospheric Sciences, 2020, 44(1): 27-38. DOI: 10.3878/j.issn.1006-9895.1906.18180
Citation: Comparative Analysis of Precipitation Distributions of Tropical Cyclones Making Landfall in East China[J]. Chinese Journal of Atmospheric Sciences, 2020, 44(1): 27-38. DOI: 10.3878/j.issn.1006-9895.1906.18180

华东登陆热带气旋降水不同分布的对比分析

Comparative Analysis of Precipitation Distributions of Tropical Cyclones Making Landfall in East China

  • 摘要: 利用CMORPH降水资料,将热带气旋(TC)登陆后的降水分为路径左侧降水(L型)和右侧降水(R型)两类,并针对登陆华东地区TC的 L型和R型降水的大气环流场、环境水平风垂直切变以及台风环流内的动热力条件进行对比分析,结果表明:2005~2014年间登陆华东地区的20例TC中包括12例L型和8例R型。总体来看,大气环流因子对于登陆华东TC降水分布起主要作用。L型降水TC高层南亚高压主要呈纬向带状分布,在登陆过程中路径左侧维持偏东风高空辐散气流,中层西风槽偏东,西太平洋副热带高压(简称副高)偏南,环境水平风垂直切变指向西南。R型降水TC高层南亚高压断裂,呈经向分布。TC路径左侧风场较均匀,右侧东南风高空辐散气流明显。副高的位置偏北呈块状,同时环境水平风垂直切变指向东北,有利于路径右侧降水。台风环流内,低层冷暖平流输送以及水汽辐合与降水落区也有较好对应关系。L型TC低层暖平流的输送使TC西南象限低层增暖,大气稳定度降低。同时水汽辐合区也主要位于西南象限,有利于TC路径左侧降水。而R型TC副高位置偏北可将南侧的东南暖湿气流向台风环流更西部输送,东北象限维持暖平流,有利于路径右侧降水发生。

     

    Abstract: In this paper, the atmospheric circulation field, vertical shear of ambient horizontal wind, and dynamical and thermal conditions within the typhoon circulations of East China-landfalling tropical cyclones (TC) for the period 2005-2014 were compared and analyzed. Using CMORPH precipitation data, the TC precipitation was classified into two categories: left side of track (L) and right side of track (R). Results showed that the 20 landfalling TCs included twelve L TCs and eight R TCs. In general, atmospheric circulation factors played a major role in the TC precipitation distributions. During landfall of the L TCs, in the upper troposphere, the South Asian high was zonally distributed and the flow was divergent on the left side of the track area, a westerly trough featured to the east mid-troposphere, and the western Pacific subtropical high was located to the south, with a southwesterly vertical speed shear of the ambient horizontal wind. In contrast, for the R TCs, the South Asian high was longitudinally oriented in the upper troposphere, then broke down. On the left side of track, wind was relatively uniform, except for a strong divergent flow on the right. The subtropical high was much further north and was blocking, and the vertical shear of the ambient horizontal wind was northeast, which was conducive to R-type precipitation. Thermal advection and water vapor convergence within the typhoon circulation corresponded well with the rainfall area. Warm advection occurred in the lower layers of the southwest quadrants of the L TCs, leading to decreasing atmospheric stability. At the same time, the water vapor convergent zone was also located in the southwest quadrant, contributing to precipitation on the left side of the TC track. For R TCs, the subtropical high was further north and transported warm, moist air on southeasterly flow to the west of the typhoon, and the northeastern quadrant always maintained warm advection, which was favorable for rainfall on the right side of the track.

     

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