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北京西北部地区短时强降水环流特征分析

发表时间:2018-12-29  浏览量:162  下载量:12
全部作者: 杨静超,王燕娜,王璐,宋楠,隋婧怡,张杰
作者单位: 北京市延庆区气象局;北京市大兴区气象局
摘 要: 利用2009年至2013年北京西北部延庆地区气象观测资料,分析短时强降水物理量特征。结果表明,短时强降水的影响系统主要可归纳为冷涡型、西风槽型和500 hPa西北气流型3类。3种类型降水发生前大气存在着较强的层结不稳定和对流不稳定,西北气流型最不稳定,冷涡型次之,西风槽型最稳定。低层水汽通量散度以西风槽型最大,冷涡型次之,西北气流型最小;冷涡型和西风槽型的水汽输送路径主要是西南低空急流携带的偏南水汽,而西北气流型则是西南低空急流携带的偏南水汽和副高外围的东南水汽输送。短时强降水发生前北京西北部地区上空存在明显的水汽辐合,大气相对湿度、液态水含量和水汽总量都较大且有明显增加。3种类型在相对湿度达到或接近饱和的层次、液态水含量和水汽总量增长幅度方面有所不同,其中冷涡型最大,西风槽型次之,西北气流型最小。水汽辐合的强弱是3种天气型环流背景下是否发生短时强降水的决定因素。
关 键 词: 大气科学;短时强降水;不稳定;水汽辐合
Title: Analysis of circulation characteristics of short-time heavy rain in northwestern Beijing
Author: YANG Jingchao, WANG Yanna, WANG Lu, SONG Nan, SUI Jingyi, ZHANG Jie
Organization: Yanqing District, Beijing Meterorological Service; Daxing District, Beijing Meterorological Service
Abstract: By using observational data from Yanqing observation stations in northwestern Beijing during the period of 2009 to 2013, physical characteristic of the short-time heavy rain (STHR) is analyzed. The results show that STHR major influence system is cold vortex, west wind trough and 500 hPa northwest airflow. There are strong stratification instability and convection instability in the atmosphere before STHR happen. Among the all types of STHR, northwest airflow type is the most unstable, cold vortex the second and west wind trough the weakest. Meanwhile the moisture flux divergence has the same order from high to low. The water vapor transportation of cold vortex and west wind trough came from southwest low level jet carrying the south water vapor. Northwest airflow has two water vapor paths, one is the same to the above path, and another one is southeastern flow on the edge of the sub-tropical high. In addition to clear convergence of water vapor, there is a large value and increased significantly of the relative humidity, liquid water content and potential water vapor in the atmosphere over northwest Beijing before STHR happen. However, the level of relative humidity reach or close to saturation, liquid water content and total amount of water vapor growth are different in the three types, from high to low, it is cold vortex type, west wind through type and northwest airflow type. The strength or weakness of the water vapor convergence in the circulation background of three types is the determinants of whether STHR occurred or not.
Key words: atmospheric sciences; short-time heavy rain; instability; water vapor convergence
发表期数: 2018年12月第24期
引用格式: 杨静超,王燕娜,王璐,等. 北京西北部地区短时强降水环流特征分析[J]. 中国科技论文在线精品论文,2018,11(24):2476-2486.
 
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