摘要
利用常规气象观测资料、NCEP资料、卫星、雷达和地面加密观测等资料,对2008年5月27—28日江西北部一次冷锋南侧(冷锋前)对流性暴雨过程进行天气动力学诊断分析和中尺度分析。结果表明:(1)对流性暴雨出现在冷锋前的主要原因是:各层槽线位置近于垂直,锋面陡峭,并出现前倾槽结构;冷锋前低层暖湿气流异常强盛,下暖湿上干冷使对流不稳定能量增强;当冷锋移近、气旋波发展东移和低空急流加强,触发了冷锋前对流不稳定能量释放。(2)本次暴雨具有明显中小尺度特征,共有4个β中尺度对流系统沿地面冷锋南侧发展东移,850hPa的中尺度辐合线、地面中低压和中尺度辐合线、云顶亮温低值区、强回波区及雷达速度图上逆风区等均揭示中小尺度扰动系统存在,且中小尺度扰动系统与暴雨雨团对应很好。
Based on the routine data,NCEP data,satellite images,radar data,and the densified observations,a dynamical diagnosis of the convection torrential rain in south of cold front on 28 May 2008 in the northern part of Jingxi Province is made.The results show that（1）the convection torrential rain south of cold front was due to the several main reasons,such as,all nearly vertical troughs at various levels,precipitous front surfaces,forwarded-tilting trough structure,extremely strong lower warm and wet air flows ahead of the cold front,greatly increased unstable energy of the convection formed by warm,wet below and dry,cold above convections,and the low-level southwest jet stream strengthening when the cold front moving closely and cyclone wave moving east.All of these factors resulted in the unstable energy release from the convection.（2）This torrential rain showed the characteristics on obvious meso and small scales that had four meso-β scale convection systems moving to the east along the ground cold front.The ground mesoscale cyclone,the mesoscale convergence line,the strong echo area,the head wind zone,and the 850hPa mesoscale convergence line,all demonstrated the presence of the mesoscale perturbation.Furthermore,mesoscale perturbation was well correlated to the convective rain cluster.
出处
《气象》
CSCD
北大核心
2009年第11期39-47,I0003,共10页
Meteorological Monthly
关键词
冷锋
对流性暴雨
对流不稳定
中尺度系统
cold front convection torrential rain convective instability mesoscale system
