摘要
利用NECP 1°×1°网格点数据资料以及卫星云图、雷达回波、区域加密自动站资料等,对2009年5月10日山东大暴雨过程进行诊断分析。结果表明:西太平洋高压加强西伸,与西风带系统结合,使中低层切变线稳定少动和降水持续,西太平洋高压外围的西南气流为暴雨区提供了充足的水汽来源;暴雨区出现在水汽通量大值区长轴方向前端、水汽通量辐合区、水汽通量矢量气旋式弯曲拐角处以及强上升速度中心区;低层辐合、高层辐散垂直结构的移动方向为水汽辐合中心的长轴方向,当其长轴前方辐合减弱时,这种垂直结构趋于减弱;地面风速辐合线在鲁西北黄河沿岸的稳定维持对大暴雨落区具有较好的指示意义,中尺度雨团位于风速辐合线西段1个纬距左右,中尺度对流云团与中尺度雨团有较好的对应关系;强回波位于850 hPa切变线东侧,与地面中尺度辐合线、中尺度雨带位置相同,回波移动方向与回波伸展方向一致,形成典型的列车效应,是造成强降水的重要原因之一。
Using NCEP 6-hourly reanalysis data with resolution 1°×1°,satellite images,Doppler-Radar data and the intensive observations of automatic weather stations,a torrential rain process in Shandong province on 10 May 2009 was diagnostically analyzed.The results show that the high over the West Pacific strengthening and extending westwards combining with westerly systems leads to the stability of shear in the lower and medium troposphere and the continuance of precipitation.The southwest airflow from the northwest side of the western Pacific high provides sufficient moisture for rain region.The torrential rain happens in the area including the top of long axis in the great positive value area of water vapor flux,convergence zone of water vapor flux,the turning of water vapor flux vector cyclonic and the central area of strong ascending velocity.The moving direction of vertical structure of convergence in the low-level and divergence in the upper level is consistent with the horizontal direction of long axis of moisture convergence center.This kind of the vertical structure tends to be weak when the convergence in front of weakens.The surface wind speed convergence stabilizing in the northwest Shangdong province along the Yellow River shows a significant indication to torrential rain areas,the mesoscale rain clusters are located one latitude space away from the west section of surface wind speed convergence line.The mesoscale convective cloud clusters have a better correspondence with rain clusters.The strong radar echoes distribute in the east of shear at 850 hPa has the same location with both surface mesoscale convergence line and mesoscale rain zone.The moving direction of echoes is consistent with that of the extending of echoes resulting in typical ＂train effect＂.It is one of key reasons to create severe precipitation.
出处
《暴雨灾害》
2010年第3期231-238,共8页
Torrential Rain and Disasters
基金
山东省科技发展计划项目"山东省极端灾害性天气特征分析及临近预警技术研究"(2009GG10008001)
山东省东营市气象局自立课题"数值预报产品在精细化预报中应用"
关键词
大暴雨
落区
环流形势
物理量诊断
中尺度分析
Torrential rain
Rain region
Circulation situation
Physical diagnostic
Mesoscale analysis
