长江中下游地区特大雷暴暴雨的诊断分析及预报

通过对1998年7月22日和1983年7月4时两例发生在鄂皖交界沿江地区特大雷暴暴雨的诊断分析，表明此类特大暴雨是由高层冷空气叠加在低空急流左前侧高湿区之上，产生持续的强烈对流降水所造成的。物理量倾向诊断结果表明：强降水中心沿着下游的增湿区和不稳定增强区发展和移动，与低层水汽辐合增强区，尤其是与“相对辐散增强区”有较好的对应关系。

Diagnosis and Forecast of Extraordinary Rainstorm in the Lower-middle Reaches of Changjiang River

By forecasting and diagnosis of extraordinary rainstorm in the lower-mi ddle reaches of Changjiang River on July 22 ,1998 and July 4, 1983, it is shown that the upper cold-air piling up left of lower jet is the main structure fe ature, diagnosis of physical parameters and its tendency shows that there are re lations between heavy precipitation or severe convection area and strong conver gence area at 850hPa to 500hPa level and strong convergence area of vapor flux in future. The rain area can be better estimated by computing the tendency than the physical parameters.