盛杰,郑永光,沈新勇. 2020. 华北两类产生极端强天气的线状对流系统分布特征与环境条件[J]. 气象学报, (0):-, doi:10.11676/qxxb2020.069
华北两类产生极端强天气的线状对流系统分布特征与环境条件
Climatology and environmental conditions of two types of quasi-linear convective systems with extremely intense weather in North China
投稿时间:2020-05-05  修订日期:2020-07-10
DOI:10.11676/qxxb2020.069
中文关键词:  线状对流系统,强雷暴大风,强降水,极端,环境条件
英文关键词:quasi-linear convective systems, severe thunderstorm wind gusts, heavy rainfall, extreme, environmental conditions
基金项目:国家重点研发计划(2018YFC1507506和2017YFC1502003)、国家自然科学基金项目(41375051,41790471,41975054),中国科学院战略性先导科技专项(XDA20100304)
作者单位E-mail
盛杰 国家气象中心 shengjie@cma.gov.cn 
郑永光 国家气象中心 zhengyg@cma.gov.cn 
沈新勇 南京信息工程大学 sxydr@126.com 
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中文摘要:
      华北线状对流系统(quasi-linear convective systems,QLCSs)精细气候分布及其所产生的极端天气特征尚不清楚。本文首先利用雷达拼图资料和客观识别方法普查2013-2018年华北191例QLCSs时空分布特征,根据其所致强对流天气的统计结果,发现华北地区至少有两类QLCSs,分别产生极端强雷暴大风和极端强降水,进一步给出了这两类QLCSs的环流形势、环境条件、地形作用和关键中尺度系统地面冷池等的特征。主要结论如下:华北QLCSs空间分布尤其是初始形成位置与大地形关系密切,京津冀的太行山和燕山山脚区域为其中的一个高发区;两类QLCSs发生月份、空间尺度、移动速度、形成时刻和维持时段等都具有显著差异;两类QLCSs的环流背景、环境条件和冷池也差别明显。强雷暴大风型QLCSs的环境大气斜压性强,中层干和大的垂直减温率造成的BCAPE、DCAPE大值区是产生极端大风的重要环境条件,地面强冷池以及0-3 km风垂直切变对前向传播起到了重要作用。强降水型QLCSs产生的降水极端性较前一类型更为突出,天气尺度强迫相对较弱,水汽条件极其充沛,地面弱冷池或地形与低层南风气流相互作用维持的后向传播是其发展和慢速移动的主要机制,也是产生极端强降水的直接原因。
英文摘要:
      The fine climatological distribution and extreme weather of QLCSs (quasi-linear convective systems) in North China are still not clear. In this paper, the spatial and temporal distribution characteristics of 191 cases, which identified by an objective identification method, in North China from 2013 to 2018, are analyzed. According to the statistics of intense weather, at least two types of QLCSs exist: one type with strong thunderstorm wind gusts and the other with extreme heavy rainfall. Furthermore, the characteristics of circulation patterns, environmental conditions, topographical process and surface cold pool that is a key mesoscale system are given for these two types of QLCS. The findings are presented as follows. The spatial distribution of QLCS in North China, especially the formation position is closely related to the Taihang Mountains and Yanshan Mountains, and the foot of these mountains is one of the highest occurrence frequency areas in Beijing-Tianjin-Hebei region, which is a feature revealed for the first time. There are significant differences in the month of occurrence, spatial scale, movement speed, formation time and maintenance time period of the two types of QLCS. The circulation background, environmental conditions and cold pool are also obviously different. The atmospheric baroclinicity of QLCSs with strong thunderstorm wind gusts is relatively obvious. The large value area of BCAPE (best convective available potential energy) and DCAPE (downdraft convective available potential Energy) caused by the dry middle layer and large temperature reduction rate is an important environmental condition for the generation of strong thunderstorm wind gusts. The strong cold pool and the vertical shear of 0-3 km wind play an important role in forward propagation. The extreme precipitation event caused by QLCS with heavy rainfall is more prominent than the previous type, usually occurs in weak weather scale forcing and plentiful vapor are supplied. The back propagation maintained by the interaction between the weak cold pool or the windward slope and the low level south wind flow is the main mechanism of development and slow movement, which is also the direct cause of extreme heavy rainfall.
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