淮河流域一次MCC的环境流场及动力分析

利用卫星云图和高空风等各种天气学资料,对2006年7月2日淮河流域发生的一次中尺度对流复合体(MCC)和淮河流域暴雨天气过程进行了大尺度环境场和物理量的诊断分析。结果表明:MCC是造成暴雨的直接影响系统,对流层中层来自北方的干侵入对MCC的生成发展起着重要作用;对流层低层华北冷空气的南下锋生、对流层中低层西南气流沿锋面爬升,为MCC的生成提供了触发机制;高低空急流耦合、天气尺度经向间接次级环流圈的形成,为MCC的生成、发展和维持提供了动力条件;对流层低层能量场特征、风速风向垂直切变特征、总指数及云图弓状回波后部干侵入区的变化等,对MCC的生成和发展有指示意义。

Environmental Streamline Field and Dynamic Analysis of a MCC in Huaihe Valley

Using the satellite cloud image and various synoptic data of upper level wind data,the large-scale environmental field and physical quantity,a mesoscale MCC and rainstorm event of Huaihe valley on July 2,2006 are diagnostically analyzed. Results show that MCC is the direct cause of rainstorm;dry invasion from north in mid-level of troposphere played an important role in developing process of MCC;the triggering system of MCC was provided by the southward frontogenesis of over North China cold air in lower-level of troposphere with southwest stream ascending upon the front in lower-mid level of troposphere.Dynamic situation for generating and maintaining MCC derived from coupled lower-upper jet streams and formation of synoptic-scale longitudinal indirect secondary circulation.Energy field features in lower level of troposphere,vertical shear of wind velocity,total index,and change of dry invasion area in rear of bow echo are all indicative to the development of MCC.