低空急流与山西大暴雨的统计关系及流型配置  

Statistical Relation and Flow Pattern of Low-Level Jet and Heavy Rainstorm in Shanxi

作　　者：苗爱梅[1] 武捷[2] 赵海英[1] 李苗[3] 

机构地区：[1]山西省气象台,山西太原030006 [2]山西省气象信息中心,山西太原030006 [3]山西省气象科技服务中心,山西太原030002

出　　处：《高原气象》2010年第4期939-946,共8页Plateau Meteorology

基　　金：山西省科技攻关项目"基于GIS的极端气象灾害预警与评估集成系统"(20090311083);山西省气象局领军人才项目"山西省气象灾害预报与对策研究"共同资助

摘　　要：利用山西省气象信息中心归档的109个测站1957—2008年的暴雨观测资料、高低空常规气象观测资料及山西省水文站的部分暴雨监测资料,研究了低空急流与山西省区域性暴雨、大暴雨以及特大暴雨的特征。结果表明:1957—2008年的192个暴雨日(区域性暴雨)、118个大暴雨日、10个特大暴雨日,有偏南风(或偏东风)最大风轴相伴出现的分别有165,110和10次,分别占其总次数的86%,93.2%和100%,表明其预示性极强;当山西大暴雨中有台风介入时,台风一般沿25°N以南西行,在其北侧与副热带高压之间形成强的东到东南风带,经鄂西北、豫西一带受西风槽或高原低值系统前部的偏南气流阻挡折向西北使副热带高压西北侧的西南气流加强,形成中尺度低空西南急流;当无台风介入时,热带辐合区一般在17°N以南,高原低值系统活跃,副热带高压与高原低值系统之间形成的天气尺度西南低空急流常常伸向黄河中游,大暴雨的落区主要在太原以南地区;根据高、低空急流的位置以及有、无台风介入,归纳出的6种大暴雨预报模型基本涵盖了山西大暴雨的落区与中、低空急流的关系,但中、低空急流的类别、位置不同以及经、纬向副热带高压、500hPa急流、西风槽、高原槽和台风等的不同配置,可使大暴雨的落区和强度不同。Based on the rainstorm data of 109 observation stations in Shanxi Province from 1957 to 2008 and the conventional observed data of upperand lower-levels of Shanxi meteorological information center and some rainstorm data of Shanxi hydrological station,the relationship of low-level jet and rainstorm in Shanxi Province-were studied.The results show that： On the 192 regional heavy rainstorm days,118 heavy rainstorm-days and 10 extremely rainstorm-days between 1957 and 2008,the largest wind axes of south wind （or east wind） occurred 165,110 and 10 times and occupieed 86%,93.2% and 100%-in total,respectively,which shows the strong predictability.-When the heavy rainstorm is affected by typhoon,the typhoon generally goes westward along the south of 25°N-and east or southeast wind belts are formed between the typhoon and subtropical high.Through the region of northwest Hubei and west Henan,those wind belts are resisted by south flow in front of the westerlies trough or Plateau Low system and turned to northwest,which forces the southwest flow on north side of subtropical high into mesoscale southwest low-level jets.When the rainstorm is not affected by typhoon,the tropical convergence area to the south of 17°N-and Plateau Low systems are active.Synoptic scale southwest low-level jet which is formed between subtropical high and Plateau Low system stretches into the middle reach of Yellow River,and the rainfall area mainly lies in the south of Taiyuan.According to the location of upperand low-level jets and the influence of typhoon,it is concluded that there are 6 predictive types which contain the relationship of low-level jet and rainfall area in Shanxi.The different location and type of midand low-level jets and the different allocation of longitudinal subtropical high,-latitudinal subtropical high,500 hPa jet,westerly trough,-Plateau-trough and typhoon-lead to the difference of area and intensity of heavy rainstrom.

关 键 词：山西大暴雨 高空急流 低空急流 预报模型 

分 类 号：P458.121.1[天文地球—大气科学及气象学]