【摘要】 为探讨西北地区东部的持续大暴雨过程成因及预警指标,利用2010年7月22~23日500~700hPa大气环流背景及天气影响系统和西峰新一代多普勒天气雷达回波资料分析,结果得到:500hPa西太平洋副热带高压外围河套地区环境场的演变高压外围低涡发展及维持,是这次持续性大暴雨过程的大气环流背景和影响天气系统,700hPa强盛的水汽场输送场与汇聚作用为这次持续性大暴雨过程提供了充沛的水汽条件,随着500hPa河套地区低涡-切变辐合系统的准静止维持造成这次持续性大暴雨过程;大暴雨前1.5~9.7km垂直方向上,存在明显的东南风场与西南风场的切变,风向随高度顺转,对应持续的暖平流;天气雷达强度回波反射率因子≥40dBz,暴雨期间维持少变;径向速度回波的水平辐合和气旋性涡旋运动与河套低涡切变天气系统对应一致;垂直液态水含量≥35kg.m2的雨团范围大、持续时间长;云顶回波高度维持在8km以上,对监测预警持续大暴雨天气具有一定指示意义。更多还原

【Abstract】 In order to analyze the cause and warning indicators of the continuous torrential rain process in the east of northwest China’s,using the material of 500hPa-700 hPa atmospheric circulation background,weather impact system and Xifeng new generation Doppler radar echo material on July 22-23,2010.the result is that:the environmental field of peripheral hetao area of 500 hPa western pacific subtropical high and the vortex development and maintain of High pressure peripheral,were the rainstorm’s atmospheric circulation background and affect the weather system.The strong water vapor transport and converge in 700 hPa provided abundant water vapor for the continuous torrential rain process.The quasi static maintain of hetao low vortex’s oscillation caused the continuous torrential rain process in 500 hPa.Before the cloudburst,in vertical direction between 1.5and 9.7km,there was an obvious shear of southeast wind and southwest field,and wind direction clockwise rotation,which was the continuous warm advection;The radar echo was over 40 dBz with little variation during rainstorm;Radial velocity echo’s level convergence and the cyclonic eddy motion is consistent with corresponding hetao vortex shear weather systems;The area of VlL greater than 35 kg.m2 were wide and continued.The ET overtop 8km has certain instruction significance in warning and monitoring system continuous torrential rain.更多还原