Journal of Arid Meteorology

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Analysis on the Cause of a Rare Rainstorm in Spring in Eastern Hexi Corridor


  1. 1. Wuwei Meteorological Bureau of Gansu Province, Wuwei 733000, China;
    2. Lanzhou Center Meteorological Observatory, Lanzhou 730020, China;
    3. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730107, China
  • Online:2015-08-31 Published:2015-08-31



  1. 1.甘肃省武威市气象局,甘肃 武威 733000;
    2.兰州中心气象台,甘肃 兰州 730020;
    3.兰州大学大气科学学院,甘肃 兰州 730107
  • 作者简介:刘菊菊(1991-),女,陕西榆林人,助工,主要从事短期天气预报及其研究工作.
  • 基金资助:



Based on the hourly precipitation from weather stations, NCEP FNL reanalysis data with 0.1°×0.1° resolution, products of FY-2E satellite and output results from Weather Research and Forecasting Model (WRF), the heavy rainfall from 7 to 9 July 2013 in east of northwest China was diagnosed. The results showed that the rainstorm was a typical southwesterly airflow rainfall process which located in northwest of subtropical high system. The development and movement of the westerly trough and plateau trough, cooperating with the southwesterly airflow and the vortex shear line in low level, were main influence systems of heavy rainfall. The coupling of upper and lower jets, the abundant water vapor together, the stronger dynamic effect and the instable atmospheric stratification facilitated the development of the heavy rainfall. The hourly evolution of TBB from FY-2E was consistent with that of rainfall intensity, when the rainfall increased dramatically at 14:00 BST on 8 July 2013, the TBB reduced to below -45 ℃ in east of northwest China. The model of WRF had a better capacity to simulate the weather process of rainstorm under complicated terrain. The evolution and magnitude of rainfall simulated by WRF from 08:00 BST 8 to 08:00 BST 9 July 2013 was similar to the observation, and the centre rainfall located in Qingyang of Gansu Province. The simulated physical quantities of wind field, specific humidity, vorticity, CAPE and vertical velocity could well reflect the process of the heavy rainfall event. The low-level airflows were lifted and converged via the trumpet-shaped topography, which caused the  increasing of cyclone and enhancing of vertical motion, cooperated with abundant water vapor, eventually caused the enhancement of heavy rainfall. Therefore, the simulated results by WRF model could be used to analyze the structure of β-scale rainfall system under rough topography, which could fill the lack of observation data.

Key words: heavy rainfall in east of northwest China, shear line, diagnostic analysis, numerical simulation, topographic effect


利用常规观测、红外云图、T639资料和区域自动站资料,对2014年 4月15~16日发生在河西走廊东部罕见春季暴雨的成因进行分析。结果表明,500 hPa天气系统为此次暴雨的主要影响系统。500 hPa东移短波槽是这次暴雨天气的触发系统,700 hPa偏南暖湿气流在低涡作用下不断向北输送水汽,为降水的维持提供了源源不断的水汽条件,下游高压脊的阻挡作用使降水持续时间较长;强水汽辐合、强上升运动出现时间比降水集中时间滞后3~4 h;K指数大值区、θse高能舌区与暴雨落区相符合;强冷空气的入侵,是降水量级增大的直接原因;变温对春季强降水的反应比变压更敏感;过程前期的高温高湿对降水的预报有一定的指示意义;锋前中尺度对流云团和锋面云带的合并是造成此次暴雨的直接原因。

关键词: 强降水, 古浪, 冷锋, 上升运动

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