2012年春季河南一次区域暴雨的诊断分析  

Diagnostic Analysis of a Regional Rainstorm in 2012 Spring in Henan

作　　者：袁小超[1,2] 

机构地区：[1]中国气象局.河南省农业气象保障与应用技术重点实验室,郑州450003 [2]河南省气象台,郑州450003

出　　处：《气象与环境科学》2015年第3期100-106,共7页Meteorological and Environmental Sciences

基　　金：中国气象局预报员专项(CMAYBY2014-040)资助

摘　　要：利用常规气象观测资料和NCEP 1°×1°间隔6 h再分析资料,采用天气学诊断分析方法,对2012年4月23-24日河南省一次春季暴雨的形成机制进行分析,结果表明:高纬冷空气沿贝加尔湖低涡后部偏北气流南下,在河套西部形成深厚低槽,低槽携带冷空气东移,在河南境内与强盛的西南急流汇合,是本次暴雨过程的天气背景。冷空气的侵入有利于西南涡的加强,而南支槽前的正涡度平流促使西南低涡沿切变线向东北方向移出,使得切变线南侧西南低空急流加强,为暴雨的发生提供了有利的动力与水汽条件。短时强降水发生前,低层能量场出现明显辐合,当低层能量场转为辐散时,能量释放,有利于短时强降水的出现。高层辐散、低空辐合的动力条件配置,使得大范围垂直上升运动加强,特别是高层散度场的下伸,利于降水释放潜热,增加大气的不稳定,进而利于强降水的发生。850 h Pa垂直螺旋度中心大值区域能很好地反映切变线、急流等与低涡相联系的天气系统,其中心强度的迅速变化能较好地指示降水的落区和强度。Based on the conventional meteorological observation data and NCEP 1 ° × 1 ° data, synoptic diagnosis method was used to analyze the formation mechanism of spring rainstorm process on April 23 to 24 of 2012. The results showed that： the high latitude cold air along Lake Baikal vortex rear northerly flowed south, and formed deep trough in the west Hetao region, and the trough carried cold air eastward and joined strong southwest jet stream in Henan region, led to the emergence of the rainstorm. The positive vorticity advection before southern trough and cold air invaded into the southwest vortex and forced the southwest vortex moving out northeast along the shear line, making the low level jet on the south side of the shear line strengthen, which provided favorable dynamic and water conditions. Before the short-time strong precipitation occurred, lower energy field appeared obvious convergence. When the low layer field turned divergence and energy released, it was beneficial for the emergence of short-time strong rainfall. Upper-level divergence and low-level convergence led to a wide range vertical upward movement strengthened. Especially when the high-level divergence field extended to the lower layer, it was beneficial for precipitation and latent heat release, which increased atmospheric instability and bene- fited the occurrence of heavy rainfall. The large value area of 850 hPa vertical helicity center could indi- cate shear line and the jet stream well, which associated with low vortex systems, and the rapid changes of its center intensity also could indicate the precipitation area and rainfall intensity well.

关 键 词：春季暴雨 西南低涡 西南急流 切变线 垂直螺旋度 

分 类 号：P458.121.1[天文地球—大气科学及气象学]