海河流域一次大到暴雨天气过程的预报分析

利用数值预报、常规天气图、各种物理量场、卫星云图、雷达资料等,对2005年7月22—24日影响海河流域的典型暴雨天气过程进行了综合分析。该过程是由高空槽、副热带高压边缘的暖湿气流和5号台风海棠减弱后的低气压云系的共同作用下产生的;其触发机制是冷空气从近地层楔入暖空气中,在高温高湿、层结不稳定等诸多有利条件下,冷空气前沿的上升气流在暖区激发出几个较旺盛的中小尺度的强对流云团造成此次的降水过程;数值预报在对流层中部冷平流入侵海河流域的时间和地点,对于强降水出现的时间和落区预报有一定的指示意义,日本模式和T213在此次海河流域强降水的落区预报上存在优势,德国模式在强降水量级的预报上最接近实况,但三家数值模式预报西太平洋副高西伸的位置不够准确,导致海河流域的降水预报的时空分布有一定误差。

Analysis of a Heavy Rainstorm Process Forecasting in Haihe River Basin

A typical rainstorm process in Haihe River Basin during 22nd-24th July 2005 is synthetically studied with numerical model,conventional observations,multiple physical indexes,satellite data and radar data etc.To be summarized,the findings from the analysis are as follows:1)the whole process was co-developed by an upper trough,the warm-moist airflow on the edge of subtropical high and the low-pressure cloud system triggered by Typhoon Haitang during its collapse phase.2)The whole process is caused by some intensely developing meso-and micro-scale convective cloud clusters which are triggered in the warm area by the updraft flow in front of cold air-mass under some favor conditions such as high temperature and moisture and stratified instability.3)The numerical modeling forecasting has some indicative sense on the time and location of the heavy rainfall and the cold advection in the middle of troposphere that intruded into Haihe River Basin.Compared to the model developed by Germany,Japanese model and T213 model have shown predominance on the location forecasting of the heavy rainfall in Haihe River Basin.However,the quantitative precipitation forecasting from German model is most close to the observations.As a whole,these three models all have poor accuracy in the location of the west edge of the subtropical high.This fact is thought to be one of the reasons causing the forecasting error in the temporal and spatial distribution of the heavy rainfall in Haihe River Basin.