摘要
利用常规观测资料结合卫星云图和诊断物理量场,对东北低压冷锋、高低空急流及中尺度辐合线形成的西北雨带与华北气旋、暖锋及切变线形成的东南雨带的双雨带暴雨影响系统、降水性质和形成机制进行综合分析。结果表明:西北雨带是东北低压冷锋前对流发展造成的强雷雨及华北气旋西北部辐合线强降水共同形成的。高低空急流耦合动力作用和中空干冷空气侵入触发大气能量释放,是冷锋前强对流降水的形成机制;中β尺度云团是强降水的主体,发生在地面三角形或梯形偏南风场中,由辐合切变线、辐合线和雷暴出流边界触发。东南部雨带为华北气旋暖锋形成的混合型强降水,气旋的发展及移动路径决定雨带位置和降水强度,由气旋暖锋和气旋西北部切变的中β尺度云团造成强降水;湿层深厚且垂直运动强盛是东南雨带降水形成机制的特点。
Based on the conventional observation data, satellite cloud images and diagnostic physical quantity field, a rainstorm process with double rain belts （northwest rain belt caused by northeast low pressure cold front, upper- lower jet and mesoscale convergence line, and southeast rain belt caused by North China cyclone, warm front and shear line） in Liaoning province were analyzed, including its affecting system, nature of precipitation and formation mechanism. The results indicate that the northwest rain belt is formed by strong thunderstorm caused by convection development before northeast low-pressure cold front and heavy precipitation on the convergence line at northwest of North China cyclone. The dynamic action of upper-lower jet before the strong convective precipitation of cold front and atmospheric energy release caused by hollow dry cold air irruption both are formation mechanism of se- vere convective precipitation before cold front. The meso-fl-scale cloud cluster is the subject of strong precipitati- on, occurring in the ground triangular or trapezoidal southerly wind filed, which is triggered by convergence shear line,convergence line and thunderstorm outflow boundary. The southeast rain belt has a mixed heavy rainfall formed by North China cyclone warm front. Rain belt location and precipitation intensity are determined by devel- opment of cyclone and its moving path. The meso-fl-scale cloud cluster from cyclone warm front and cyclone northwest shear create heavy rainfall. The deep wet layers, powerful and prosperous vertical movement are the fea- ture of southeast rain belt rainfall formation mechanism.
出处
《气象与环境学报》
2015年第6期34-42,共9页
Journal of Meteorology and Environment
基金
辽宁省科技厅重点项目(2011210001)
中国气象局预报员专项(CMAYBY2014-014
CMAYBY2012-011)
辽宁省气象局课题"辽宁气旋双雨带暴雨的动力条件研究"(201416)共同资助
关键词
双雨带
抽吸作用
中β尺度云团
露点锋
Double rain belts
Pumping action
Meso-fl-scale cloud cluster
Dew-point front
