The cumulus merging processes in generating the mesoscale convective system （MCS） on 23 August 2001 in the Beijing region are studied by using a cloud-resolving mesoscale model of MM5. The results suggest that the m...The cumulus merging processes in generating the mesoscale convective system （MCS） on 23 August 2001 in the Beijing region are studied by using a cloud-resolving mesoscale model of MM5. The results suggest that the merger processes occurred among isolated convective cells formed in high mountain region during southerly moving process play critical role in forming MCS and severe precipitating weather events such as hailfall, heavy rain, downburst and high-frequency lightning in the region. The formation of the MCS experiences multi-scale merging processes from single-cell scale merging to cloud cluster-scale merging, and high core merging. The merger process can apparently alter cloud dynamical and microphysical properties through enhancing both low- and middle-level forcing. Also, lightning flash rates are enhanced by the production of more intense and deeper convective cells by the merger process, especially by which, the more graupel-like ice particles are formed in clouds. The explosive convective development and the late peak lightning flash rate can be found during merging process.展开更多
基金the Chinese National Natural Science Foundation of China （Grant Nos. 40575003 and 40333033） the Chinese Academy of Sciences Innovation Foundation （Grant Nos. KZCX3- SW-213 and KZCX3-SW-225） the Key Project of the Ministry of Science and Technology of China （Grant No. 2001BA610A-06）.
文摘The cumulus merging processes in generating the mesoscale convective system （MCS） on 23 August 2001 in the Beijing region are studied by using a cloud-resolving mesoscale model of MM5. The results suggest that the merger processes occurred among isolated convective cells formed in high mountain region during southerly moving process play critical role in forming MCS and severe precipitating weather events such as hailfall, heavy rain, downburst and high-frequency lightning in the region. The formation of the MCS experiences multi-scale merging processes from single-cell scale merging to cloud cluster-scale merging, and high core merging. The merger process can apparently alter cloud dynamical and microphysical properties through enhancing both low- and middle-level forcing. Also, lightning flash rates are enhanced by the production of more intense and deeper convective cells by the merger process, especially by which, the more graupel-like ice particles are formed in clouds. The explosive convective development and the late peak lightning flash rate can be found during merging process.
基金National Natural Science Foundation of China （NoA0905019, 40975023 ） The R ＆ D Special Foundation for Public Welfare Industry （Meteorol- ogy） （No. GYHY200906003）
文摘通过对合肥多普勒天气雷达2003～2006年逐年7月份回波资料的普查,统计和总结了安徽大别山地区对流云的合并规律,并对一次典型的对流云合并过程进行了实例分析。结果表明:(1)在影响安徽的诸多天气系统中,华北低槽型天气背景下大别山区发生对流云合并的几率最大;(2)对流云合并普遍发生在午后时段;(3)对流云合并后,雷达回波面积增大的概率在70%以上,回波强度增大的概率为66.3%,生命史主要集中在90～240 min.
