河南2010年9月5～7日连续性暴雨过程分析

Continuous Heavy Rain Analysis in Henan Province between September 5-7,2010

利用常规资料和NCEP再分析资料,对2010年9月5～7日河南省出现的连续性暴雨过程进行了分析.结果表明,切断低压和南支槽稳定维持造成了连续降水;中低空的低槽、低涡、切变线是造成暴雨的直接影响系统,中低空急流起了一定作用;高空辐散抽吸作用,与低空较强辐合的叠加,有利于上升运动发展加强,为暴雨提供了有力的动力条件;中低层湿Q矢量散度辐合区的重叠,能较好地对应暴雨落区;较弱的动力条件下,热力对流引起的暴雨面积较小;强烈的动力作用引起的暴雨面积大、强度大、分布集中;中低空的水汽输送,为暴雨提供了充沛的水汽;中层西南气流输送的水汽来源于孟加拉湾,低空偏南、东南和偏东气流输送的水汽来源于黄海、东海和南海.

Using the conventional and NCEP reanalysis data, continuous heavy rains in Henan between September 5 -7, 2010 were ana- lyzed. The results showed that the stable cutoff low and south branch provided a circulation background for the continuous heavy rainfall, the middle and low level branch, vortexes and shearJwere direct influence systems of the heavy rainfall, jet stream at medium and minimum alti- tude also played an important role. The upper level divergence and low level convergence increased vertical speed and provided motivation conditions for the heavy rainfall. The middle and low level ageostrophic wet Q vector convergence echoed with the influence area of heavy rain- fall. In weak dynamical conditions, thermal convection produced less heavy rainfall. In strong dynamical conditions, area, intensity and distri- bution of heavy rainfall were enhanced. Warm and moist air of the middle and low level was transferred continuously to the precipitation area. The middle level vapor in southwest China is from Bay of Bengal, low level vapor in south, southeast and east China from the Yellow Sea, East China Sea, and South China Sea.