摘要
利用美国NCEP再分析资料结合地面加密自动站、卫星、雷达等常规资料,对2006年7月3日苏北东部地区一次最强的梅雨锋大暴雨过程进行了诊断分析,揭示了此次过程不同尺度系统的特征。结果表明:(1)此次过程是一次非典型的梅雨锋对流性暴雨,贝加尔湖稳定、强大的高压脊是引发大暴雨过程的大尺度背景条件。(2)高空槽、西南涡、低空急流以及地面气旋为大暴雨提供了强劲的动力和水汽条件。(3)α中尺度上,该暴雨系统的垂直结构为中低层强烈的辐合和上层的辐散,其中心有着强烈的上升气流;同时在中高层,系统的北侧有一个高空急流强迫产生的次级环流。地面多个中尺度涡旋的上升气流汇合成高低空急流耦合产生的次级环流的上升支,这种中尺度暴雨系统的三维结构为强暴雨的形成提供了持久必要的动力、水汽和不稳定性条件。(4)云图上对应一个MCS的发展演变,雷达上弓形回波对应的速度图上的"逆风区"和"中气旋"则是这次过程中局地短时强降水、龙卷的γ中尺度系统。
In this paper,a most severe Meiyu front heavy rainfall was analyzed by use of the satellite imagery, Doppler radar and ground-based observations data,and the characteristics at different scales of the this weather system were revealed.The results are summarized as follows：（1） This process is an atypical Meiyu front convective storm,with the Baikal blocking high as background conditions.（2） Synoptic scale high-altitude trough,southwest vortex,low-level jet and ground cyclone provided the heavy rainfall with strong impetus and moisture conditions.（3） On meso-αscale,the vertical structure of the storm system was the strong low-level convergence and upper-level divergence,with a strong updraft in its center.At the same time,in the high-level,on the north side of the system there was a high-altitude jet which forces to produce a secondary circulation.And the secondary circulation of ascending branch,caused by jetstream of many mesoscale vortices on ground,provides the heavy rainfall with persistently necessary power,water vapor and unstable conditions.（4） There was an evolution of MCS on the cloud imagery.The＂counter -wind zone＂and mesocyclone on the speed map corresponding to the bow echo of radar were just the meso -γsystem of tornadoes leading to the short-term heavy rainfall.
出处
《气象》
CSCD
北大核心
2011年第4期432-438,共7页
Meteorological Monthly
关键词
梅雨锋暴雨
多尺度特征
中尺度暴雨系统
诊断分析
Meiyu front heavy rain
multi-scale characteristics
mesoscale heavy rain system
diagnostic analysis
