大气科学2011，Vol.35Issue(5)：945-962,18.
引发华北特大暴雨过程的中尺度对流系统结构特征研究
A Study of Structure of Mesoscale Systems Producinga Heavy Rainfall Event in North China
摘要
Abstract
By using routine observation, FY2C TBB and NCEP reanalysis data, a diagnostic analysis and simulation study have been performed to study the mesoscale systems producing the heavy rainfall event in North China during 22 - 24 July 2005. The results show that two mesoscale convective systems which developed within the inverted ty-phoon trough directly resulted in the heavy rainfall event The mesoscale vortexes were firstly formed in the middle troposphere Vvhen the mesoscale convective system matured, and then developed to the lower troposphere. Water vapor convergent centers are mainly concentrated near the surface boundary layer. Easterly inflow pushed water vapor to the rainfall area and upward branches of the secondary circulation transported the water vapor to the middle and upper troposphere. Although the water vapor convergence in the surface boundary layer is very important, the rainfall amount depends on the vertically integrated moisture flux convergence. Dry and cold air apparently intruded into the rainfall area from the high troposphere in the development of heavy rainfall and it was located between 600 and 300 hPa. The dry intrusion in upper levels overruns that in low levels. The dry intrusion enhanced moist instability and promoted the development of convection and the formation of mesoscale vortexes, and then the enhancement of precipitation. In the development of the heavy rainfall, the boundary layer jet was induced due to the local heating of terrain in North China in the night. Precipitation and dry intrusion further enhanced the boundary layer jet and strong wind in upper levels emerged accordingly. Jets and heavy rainfalls have positive feedback through the secondary circulation. The coupling among the boundary layer jet, upper and lower tropospheric jet streaks played an important role in this heavy rainfall event.关键词
特大暴雨/中尺度对流系统/水汽/干冷侵入/边界层急流Key words
heavy rainfall, mesoscale convective system, water vapor, dry intrusion, boundary layer jet分类
天文与地球科学引用本文复制引用
赵宇,崔晓鹏,高守亭..引发华北特大暴雨过程的中尺度对流系统结构特征研究[J].大气科学,2011,35(5):945-962,18.基金项目
中国气象局武汉暴雨所暴雨研究开放基金项目IHR2008K03,国家自然科学基金资助项目41075043,南京信息工程大学科研基金项目20100314 （）
