摘要
利用多普勒雷达等多种观测资料,分析2003年6月22日发生在湖北省安陆北部的山洪,并初步概括了引发山洪暴雨的概念模型,结果表明:①引发安陆山洪的暴雨强度大、持续时间短,强降雨带(团)具有明显的中β尺度特征,山洪爆发地区的强降水由中β尺度降水带上与深厚对流云活动有关的中γ尺度强降水雨团造成;②引发山洪暴雨的概念模型可以描述如下:在有利的大尺度环流背景及高低空急流耦合下,天气尺度系统影响产生大范围降水,当受外界强迫或者存在大气对流不稳定度增强和对流触发机制时,大范围降雨带上产生中β或中γ尺度强对流雨团导致大暴雨甚至特大暴雨天气,在有利的地形条件下爆发山洪,特别是在山区前期发生了降水,土壤湿度大,地表渗透系数小的情况下极易发生。
With Doppler radar data, analyzed was the flash flood in the northern Anlu in Hubei Province on 22 June 2003, and a conceptive model of heavy rain triggering flash floods was developed. The results show: ① The heavy rain process triggering the Anlu flash floods has the characteristics of high intensity and short duration, and its mesoscale rainfall clusters have obvious meso-scale characteristics. The severe rainfall in the flash flood area was resulted from the meso-γ-scale rainfall clusters, which were related to the activities of deep convective clouds on the meso-β-scale rain band. ② The conception model of the heavy rainfall triggering flash floods can be described as: Under the context of favorable large-scale atmospheric circulation and coupling of upper and low level jets, synoptic-scale systems lead to large-scale rainfall. When there exists environmental forcing or triggering mechanisms of air instability, the meso-β/γ-scale heavy rain clusters on large-scale rain bands result in severe heavy rainfall, and lead to flush floods or even disastrous flash floods, in combination with favorable topography, especially in the mountainous areas with large soil humidity and small surface permeating coefficient owing to the previous rainfall.
出处
《气象科技》
2005年第3期245-249,共5页
Meteorological Science and Technology
基金
湖北省地质灾害预报预警项目资助
