摘要
利用常规气象观测资料以及NCEP 1°×1°再分析资料,对2015年5月5—6日茂名市局地强暴雨过程的环流背景及影响系统进行分析,同时给出降水物理因子诊断。结果表明:该次局地强暴雨是在两槽一脊的环流形势背景下,位于孟加拉湾附近的南支波动配合东路冷空气渗透造成的强降水;5月初,随着西南季风的爆发,来源于北部湾的西南急流和南海的水汽辐合是两支主要的水汽输送带,并且高水汽通量区与暴雨落区密切相关;该次暴雨过程,高层辐散先于低层辐合,高低层的抽吸作用有利于暴雨的触发;粤西地区位势不稳定能量不断累积,为该次暴雨的形成提供了不稳定能量条件。
Conventional observations as well as NCEP reanalysis are used to analyze the circulation background and governing systems for a local unusually heavy rain in Maoming in May 5 -6, 2015 and to di- agnose the associated physical factors of the precipitation. The result is shown as follows. The intense rain was caused as southerly waves near the Bay of Bengal acted with cold air from an eastward route against the circulation background of two troughs allocated with a ridge. In early May, with the outbreak of the south- west monsoon, a southwesterly jet stream from the Beibu Bay and the convergence of water vapor over the South China Sea are two main channels of water vapor transportation, with high correlation between high wa- ter vapor flux and the area of heavy rain. For the rain process of interest, upper-level divergence precedes low-level convergence and the sucking effect in both the upper and low levels helped trigger the heavy rain, and the constantly accumulated energy of potentially instability over the western Guangdong was the condition of instable energy for the generation of the heavy rain.
出处
《广东气象》
2016年第6期16-19,共4页
Guangdong Meteorology
基金
广东省茂名市气象局气象科技计划项目"西南季风活动对茂名汛期重要天气的影响(201501)
关键词
天气学
局地强暴雨
环流形势
水汽通量
不稳定能量
茂名市
synoptics
local unusually heavy rain
circulation pattern
water vapor flux
instability en- ergy
Maoming city
