摘要
利用常规观测资料、逐小时自动站资料、TBB资料和NCEP再分析格点资料,对2007年7月18日河北省东北部和南部局地暴雨过程进行了诊断分析。结果表明:在相同的影响系统作用下,河北省不同区域暴雨的形成机制却不同,高、低空急流及其耦合条件下急流和暴雨相互作用是上午东北部暴雨的成因,低空急流直接输送水汽,在FY-2C云图上表现为云顶TBB<-70℃近乎圆形的中-α尺度强对流云;而下午河北南部强降水是在高温高能、层结不稳定的有利条件下,地面冷锋及锋前低压形成的强辐合抬升触发不稳定能量释放产生的强对流天气,对应云图上为最低TBB在-80℃以下的准东西向带状对流云系。逐小时地面自动站资料分析的流场和计算的地面湿静力能对此类夏季强对流天气的预报具有指示意义。
A local heavy rainstorm in northeast and southern Hebei on July 18, 2007 is analyzed by using conventional observation data, hourly data of automated weather station, TBB data and NCEP 6 hour re-analysis data. Conclusions are drawn that although in the same synoptic system, the rainstorm formation mechanism is different in different regions. It is revealed that the upper- level and low-level jet streams as well as the interaction between the positive feedback of the jets and rainstorm are the main reasons causing the north-east rainstorm in the morning. The vapor is transported by low-level jet stream. There are round-like meso-a convective cloud clusters with TBB less than -70℃ in the image of the FY-2C. The severe event in southern Hebei in the af- ternoon occurred under the favorable conditions of the high-temperature, high-energy and unstable stratification when instable energy was triggered and released by the cold front and the low -pressure before the front. In the corresponding images there are quasi-trans-meridian convective cloud clusters with minimum TBB less than - 80℃. The streams and surface humid-static energy calculated from automatic weather stations data have significant indication to prediction of this sort of summer strong convection weather.
出处
《气象》
CSCD
北大核心
2008年第9期47-56,共10页
Meteorological Monthly
关键词
局地暴雨
急流
次级环流
湿静力能
local heavy rainstorm jet streams secondary circulation humid-static energy
