一次大暴雨过程低空急流脉动与强降水关系分析

应用香港天文台提供的时空分辨率都非常高的风廓线雷达资料对深圳2005年8月19—20日大暴雨过程强降雨时段进行了详细分析。结果表明，风廓线雷达资料每小时风场揭示每次强降水的发生都对应一次西南急流的迅速加强和向下扩展。低空急流指数I可以说明低空急流的脉动向地面扩展程度与中小尺度降水的密切关系，对强降水的出现及雨强大小有一定的预示性。

Relationship between Low Altitude Jet Stream and Heavy Precipitation in a Heavy Rainfall Event

By analyzing high spatial and temporal resolution data of wind profile radar provided by Hong Kong Observatory, a thorough study of the heavy rainfall from 19 to 20 August 2005 in Shenzhen is conducted. It is proved that the hourly wind field derived from wind profile radar data could reveal the correspondence between the occurring of every heavy rain and the rapid strengthening and downward expanding of the southwest jet stream. The low-level jet stream index I illustrates a close relation between the extent of downward expanding of low-level jet stream and the meso-micro scale precipitation. This index is therefore significant for forecasting magnitude and intense of heavy precipitation.