Journal of Arid Meteorology

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Multi-scale Diagnosis of a Strong Precipitation Process in the North of He’nan

LI Gaiqin1, DU Liya1, ZHAO Haiqing2, XU Qinge1, WU Limin1, WANG Cong1   

  1. 1.Puyang Meteorological Bureau of He’nan Province, Puyang 457000,China;
    2.Zhengzhou Meteorological Bureau of He’nan Province, Zhengzhou 450005,China
  • Online:2016-11-01 Published:2016-11-01

豫北一次强降水过程的多尺度诊断

李改琴1杜丽娅1赵海青2许庆娥1吴丽敏1王聪1   

  1. 1.河南省濮阳市气象局,河南濮阳457000; 2.河南省郑州市气象局,河南郑州450005
  • 作者简介:李改琴(1966-),女,高级工程师,主要从事暴雨及强对流天气研究. E-mail:pysligaiqin@163.com

Abstract:

A strong precipitation process occurred on 8 July 2013 in Puyang of He’nan. By using conventional observation data, NCEP reanalysis data, automatic meteorological station data, satellite cloud images and Doppler weather radar data, the meso-scale characteristics and the causes of this strong rainfall were diagnosed and analyzed. Results are as follows: (1)It was a shear line storm process. The high-level trough moving eastward, subtropical high strengthening and moving northward, southwest warm moist flow strengthening, shear line at the low and middle levels and surface inverted trough developing were circulation characteristics. Heavy precipitation occurred in the unstable atmosphere, at the same time, its environmental field characteristics were low-level plenty vapor and severe convergence and high-level severe divergence. Heavy rain center occurred near the warm shear line on the top of “人” shaped shear at low-middle level, and the cold and warm air cyclonic strongest convergence region on the top of surface inverted trough. (2)On cloud pictures, β-scale convective clouds developing strongly along the convergence line of surface inverted trough moved northward and merged the local convective clouds over Puyang into α-scale MCS, and the convective strong precipitation area located in the strong convective region and nearby the front of the MCS. Here the lowest TBB reached 203 K. (3)On radar pictures, multiple mesoscale short band echoes merged into strong vortex zonal banded echo and moved northward. This banded echo and convective echo near Puyang merged into strong echoes, which rounded and stranded over Puyang, and the strong precipitation formed. Low-level southeast inflow and middle-level large strong southwest inflow formed strong mesoscale convergence rotating wind field around radar station, which increased updraft movement and formed extreme convective strong precipitation.

Key words: strong rainfall, shear line, low level jet, MCS, surface inverted trough

摘要:

2013年7月8日河南濮阳发生强降水天气,利用常规天气观测资料、NECP再分析资料、地面自动站加密资料、卫星云图和天气雷达产品,诊断此次强降水过程产生的原因及中尺度特征。分析表明:(1)此过程属切变线暴雨过程,高空低槽东移、副热带高压加强北上、西南暖湿气流加强、中低层切变线和地面倒槽发展是强降水过程的环流特征。强降水发生在大气层结不稳定区域,低层水汽充沛,有低层强辐合、高层强辐散的环境场特征。降水中心位于中低层“人”字型切变顶端右侧暖切变线附近、地面倒槽顶端冷暖空气气旋性辐合最强区域;(2)沿倒槽辐合线强烈发展的β中尺度的对流云团东北移与濮阳周围发展的对流云团合并加强,形成较强的中α尺度的对流系统(MCS),对流性强降水落区处于MCS的前端对流发展旺盛区及附近,此处云顶亮温(TBB)值达到最低(203 K);(3)多普勒雷达回波图上,多条中尺度回波短带汇合加强,形成“人”字型带状回波北抬,与濮阳附近发展的对流回波合并加强,强回波在濮阳当地打转滞留,造成强降水;径向速度图上,低层较大的东南风入流和中层大范围强盛的西南风入流在雷达站周围形成中小尺度的强旋转辐合风场,使对流上升运动增强,造成极端对流性强降水。同时此处也是地面中小尺度的气旋性辐合处。

关键词: 强降水, 切变线, 低空急流, 中尺度对流系统, 地面倒槽

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