下击暴流形成机理及监测预警研究进展

A Review of Downburst Genesis Mechanism and Warning

下击暴流指对流单体强下沉气流引发的地面或地面附近的爆发性辐散出流,单个下击暴流会导致千米尺度地面强阵风,而下击暴流簇可导致较大范围间断性地面灾害性强阵风,其形成机制亦不限于强下沉气流辐散。文章回顾了下击暴流的界定,然后分为孤立风暴产生的下击暴流和中尺度对流系统内嵌的下击暴流两种情况进行讨论,内容包括对流大风和下击暴流产生的物理机理、风暴结构特征以及基于多普勒天气雷达的预警技术。在上述回顾基础上,对下击暴流形成机理及监测预警难点进行了讨论,提出了与下击暴流相关的亟需研究的问题。

The downburst is the outburst of divergent flow on or near the ground induced by a strong convective downdraft.A single downburst affects a small area of several kilometers,and the downburst cluster can extend over several hundreds of kilometers resulting in many noncontinuous surface damaging gusts.Its enhancing mechanism may not be limited to the strong downdraft divergent outflow.This article reviews the definition of downburst,and dicusses downbursts under two different situations.One is the downburst induced by isolated storms and the other is the downbursts embedded in mesoscale convective systems,including the formation processes of downburst and warning technology of downburst based on Doppler weather radar.On the basis of the above review,the formation mechanism of downburst and the difficulties of warning are discussed,and the much-needed issues related to downburst are listed.