摘要
利用卫星云图、多普勒雷达产品以及探空资料,结合NCEP/NCAR再分析资料,对2003年7月4～5日淮河流域大暴雨过程发生的环境场条件、强降水的中尺度特征、低空急流与能量锋的配置对强降水天气的影响等进行了详细的天气学分析,并对大气正压非平衡强迫、低空急流与能量锋相互作用对强降水天气发生、发展与持续过程中的影响进行了动力诊断。结果表明:这次梅雨锋暴雨过程,暴雨区上空气柱内水汽较少,孟加拉湾与南海地区向暴雨区输送的水汽占据主导地位。暴雨区的平均散度与垂直速度变化与强降水天气变化比较一致。对流层低层能量锋与低空急流的配置及其相互作用对强降水天气的发生、发展和维持具有重要影响。当低层能量锋与低空急流处于同时强的配置状态时,强降水天气发生并持续;当两者处于一强一弱或两者皆弱的配置状态时,则没有强降水天气发生或持续。正压非平衡强迫对强降水启动作用较大,而湿斜压热动力相互作用对强降水天气持续影响较大,是导致强降水过程维持的主要动力机制。
The heavy flood over Huaihe River valley in the summer of 2003 is another serious flood event after 1991. Three long life-cycle severe heavy rainfall induced the flood from 29 June to 11 July 2003. The most severe heavy rain happened during 4-5 July, in which the intensive rain period was from 12：00 on 4 to 06：00 on 5 July, with Chuzhou in Anhui Province isolated by 24 h precipitation of 273.7 mm. By use of the upper-air sounding, satellite and Doppler radar data, and NCEP/NCAR reanalysis data, environmental condition, mesoscale feature of rainstorm and the effect of reaction between low jet and energy front on heavy rain is analyzed and the maintenance mechanism of heavy rain is diagnosed. The results are as follows： （1） Moisture transporting to the heavy rain area from the South China Sea and the Bay of Bengal is main moisture source supplying severe precipitation because the air above heavy rain area is more dry before precipitation. （2） The starting and terminating time for severe precipitation are consist-ent with the increase and weak of convergence and vertical motion. （3） There are the effects of reaction between low jet and energy front on the occurrence and maintenance of severe precipitation. The severe pre-cipitation will occur and maintain when couple condition between low jet and energy front, and otherwise, the severe precipitation will terminate. （4） The barotropic non-equilibrium force is contribution to the occurrence of heavy rain, but the baroclinic coupling forces between dynamic and thermodynamic fields play main role in the maintenance of heavy rain.
出处
《高原气象》
CSCD
北大核心
2009年第6期1316-1325,共10页
Plateau Meteorology
基金
国家自然科学基金项目(40675032
40930951)资助
关键词
梅雨锋暴雨
低空急流
能量锋
正压非平衡强迫
斜压热动力相互作用
Heavy rainstorm on Meiyu front
Low jet
Energy front
Barotropic non-equilibrium force
Reaction between dynamic and thermodynamic fields
