Journal of Arid Meteorology

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Analysis on a Severe Convective Weather Process in Weinan of Shaanxi Under Long-wave Adjustment Condition


  1. Weinan Meteorological Bureau of Shaanxi Province, Weinan 714000, China
  • Online:2015-08-31 Published:2015-08-31



  1. 陕西省渭南市气象局,陕西 渭南 714000
  • 作者简介:武麦凤(1972-),女,陕西蒲城人,高级工程师,主要从事中短期天气预报研究.
  • 基金资助:



Based on the conventional and intensive meteorological data,FY-2E satellite images and Doppler radar data, a severe convective weather which occurred during the evening of July 1, 2014 in Weinan of Shaanxi was analyzed. The results indicated that the severe convective weather was caused by the interaction of cold air which spread to the south constantly from the bottom of the cut-off low and mesoscale shear line in mid-latitude region during the process of 500 hPa long-wave adjustment. Large vertical temperature gradient had good guiding significance to the potential forecast of severe convective weather in Weinan. Terrain effect caused the enhancement of the lower vertical wind shear and the formation of ground small-scale convergence line. The dry air in middle level was involved into the convective clouds owe to the enhancement of vertical wind shear, which led to the increase of cloud condensation nuclei. The surface temperature rose and the humid increased after the airflow passing through Weihe river, which was beneficial to the transformation of weather phenomenon from hail to short-term rainstorm. In addition, the small scale ground convergence line further triggered off convective instability energy.Therefore, the strong vertical wind shear and the low-level convergence acted together to cause the enhancement of the convective clouds and rainfall intensity.

Key words: long-wave adjustment, vertical temperature gradient, vertical wind shear, terrain effect


利用常规高空和地面观测资料、FY-2E卫星云图资料、多普勒天气雷达及地面加密气象站资料,对2014年7月1日发生在陕西渭南的一次强对流天气过程进行分析。结果表明:本次强对流天气过程是在500 hPa长波调整过程中,冷空气不断从切断低压底部扩散南下,与中纬度中尺度切变线相互作用所致;垂直温度梯度大对渭南市强对流天气有较好的潜势预报意义;地形作用导致中低层风向垂直切变增强和地面小尺度辐合线形成。其中,垂直风切变的增强致使中层干空气卷入对流云团中,新鲜空气补充了云凝结核源,经过渭河之后,近地面气温升高、相对湿度增大,有利于冰雹转成短时暴雨。地面小尺度辐合线触发了不稳定能量进一步释放;强的垂直风切变和低层辐合共同作用,使对流云团增强,降雨强度增大。

关键词: 长波调整, 垂直温度梯度, 垂直风切变, 地形作用

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