一次下击暴流过程的多普勒雷达特征分析

本文主要利用高空及地面常规观测资料、卫星遥感监测资料和C波段多普勒雷达监测资料,对2012年6月20日下午14时30分产生在齐齐哈尔东部的下击暴流过程进行分析。结果发现:这次下击暴流主要是前期低层辐合并且配合了较好的层结不稳定条件使得对流发展起来;后期由于700 hPa干空气的卷入使得降水粒子在下降过程中蒸发,气团加速,最后在地面附近产生辐散性大风。在过程开始之前可以根据雷达探测到的反射率因子核高度的不断下降以及不同高度速度场的辐合辐散特征提前几分钟预警出下击暴流过程。

Doppler radar characteristics of once downburst process

Using the conventional high and ground observations data, satellite remote sensing data and C-band Doppler radar surveillance data to analyze a downburst process that happened in the east of Qiqiha＇r at 14：30 on June 20, 2012.The results show that, low-level convergence with stratification unstable makes the convection de- velope at early stage, then the involvement of dry air from 700 hPa makes the precipitation particles evaporate during descent, the air mass accelerates, and finally form the divergence of wind near the ground. Before the pro- cess begins, downburst warning can be made a few minutes early according to a high degree of reflectivity factor nuclear declining and the characteristics of convergence and divergence at different height velocity field.