摘要
2014年5月8—11日,江门市出现了连续4 d的大暴雨局地特大暴雨降水过程,造成江门各地出现不同程度的洪涝灾害。利用地面常规自动气象站资料、区域气象站资料、雷达图和NCEP/NCAR逐6 h 1°×1°再分析资料,从降水特征、环流背景、主要影响系统以及各主要物理量特征,分析水汽、动力和热力等条件,探讨强降水的成因。结果表明:该次持续性大暴雨过程是在高低空有利的环流背景下产生的,高空槽、南亚高压、西南急流和地面低槽是大暴雨的主要影响系统;强盛的西南气流给华南源源不断地输送水汽,江门上空水汽通量超过12 g·h Pa^(-1)·m^(-1)·s^(-1);暴雨发生期间边界层的水汽辐合最为显著,对大暴雨有重要贡献;强降水与低空的正涡度中心有很好的对应;高层辐散强于低层辐合,并有强烈上升运动;暴雨中心低层为高温高湿,大气不稳定;前期的低层逆温,积聚能量,有利于强降水的发生;垂直风切变较小,也有利于降水的维持。
On May 8-11, 2014, a rain process, which was marked with unusually large amount of rain in some localities, occurred in Jiangmen that lasted continuously for 4 days, causing flooding damage of various intensity in different parts of the city. With conventional data and automatic weather stations data, regional meteorological observation stations data, radar echoes and 6-hourly 1°×1° reanalysis from NCEP/ NCAR, we analyzed the conditions of water vapor, dynamics and thermodynamics and studied the causation for this intense rain from the rain characteristics, circulation background, main affecting systems as well as different main physical quantities. The result is shown as follows. The sustained heavy rain was generated in faw）rable background of both upper and low levels of circulation ; upper-level troughs, the south Asian high, southwesterly jet streams and surface low-pressure troughs are the systems that have the main influence. Vig- orous southwesterly airflows kept transporting water vapor to the south of China so that its flux was more than 12g·hPa^-1·m^-1·s^-1 For the boundary, layer, water vapor was the most significant during the heavy rain, having important contribution to it. The intense rain corresponded well with the center of positive vorticity at the low level. Upper-level divergence was stronger than low-level convergence with intense ascending motion. The low-level rain center was high in both temperature and humidity, making the atmosphere instable. Low-level temperature inversion prior to the rain helped energy accumulate and favored the generation of the intense rain. Vertical wind shear was also small, which also contributes to the maintenance of the rain.
作者
黄青兰
林雪仪
吴斯敏
HUANG Qing-lan LIN Xue-yi WU Si-min(Meteorological Bureau of Jiangmen City, Jiangmen 52903)
出处
《广东气象》
2016年第5期10-14,共5页
Guangdong Meteorology
基金
江门市气象局气象科技项目(201403)
关键词
天气学
大暴雨
物理量
江门
synoptics
unusually heavy rain
physical quantity
Jiangmen
