摘要
利用常规气象资料和NCEP再分析资料,从前期天气背景、大气环流演变及产生持续性强降雨的动力、热力和水汽等条件,分析了2008年6月广西出现的一次持续性强降雨过程。结果发现:这次持续性强降雨过程期间,500 hPa环流形势稳定,高空西风小槽呈阶梯状持续下滑影响广西,不断诱发暴雨出现;200 hPa广西处于南亚高压东部脊区和高空西风急流出口区右方,风速辐散明显,在高低空急流耦合作用下,华南出现了正反两支垂直环流,广西上空辐合上升运动明显,为强降雨的出现提供了极好的动力条件;南海季风暴发和副热带高压在华南沿海的稳定维持,使得华南低空形成了印度洋和南海两支水汽通道,为暴雨区上空提供了源源不断的水汽;高温、高湿、高能的热力条件,有利于扰动的形成和对流不稳定能量产生,为广西持续性暴雨提供了必要的能量条件。
Based on the weather background, atmospheric circulation evolution and the meteorologi- cal conditions, including dynamic, thermodynamic, water vapor and so on conditions, the persistent torrential rain weather in Guangxi in June of 2008 is examined by using the observation data and NCEP reanalysis data. The results showed that during the course of the continuous heavy rainfall, 500 hPa circu-lation situation stable, high-altitude westerly trough continued deeline as a ladder and influence Guangxi, which constantly evoked heavy rainfall. The high-level wind speed dispersed in Guangxi at 200 hPa be- cause of Guangxi lied to the eastern ridge of high pressure zone in South Asia and exports of upper-level westerly jet right areas. Because of the reciprocity of the upper-low level jet, Southern China generatedpositive and negative of two vertical circulation and Guangxi converged ascending motion, which provided excellent dynamic force of heavy rainfall. The eruption of the South China Sea monsoon and the stably maintaining in low-altitude southern China of the subtropical high-pressure system offered water vapor continuously, which formed the Indian Ocean and the South China Sea two water vapor channels. In ad- dition, the high temperature and high humidity and high energy are the necessary thermal energy condi- tions for the generation of continuous heavy rain in Guangxi, which is propitious to the development and the generation of convective instability energy.
出处
《气象与环境科学》
2012年第1期26-31,共6页
Meteorological and Environmental Sciences
基金
中国气象局预报员专项项目(CMAYBY2011-039)资助
关键词
持续性
强降雨
成因
高低空急流
垂直环流
persistence
heavy rainfall
cause
upper-low level jet
vertical circulation
