诱发泥石流灾害的四川盆地大暴雨过程分析

Analysis of a Heavy Rain Process Causing Mud-rock Flow Calamity in the Sichuan Basin

通过对 2 0 0 1年 9月 18～ 2 0日诱发泥石流灾害的四川盆地西、北部大暴雨过程的分析 ,得出几点认识 :(1)诱发泥石流灾害的暴雨与前期雨日、暴雨强度及地质、地貌有关 ,此类暴雨预报应以地质、地貌特征划分区域为妥。 (2 )这次华西秋季大暴雨过程中前、后期 5 0 0hPa影响系统不同 ,这是一般暴雨所少见的。 (3)大暴雨发生在对流层中低层为气旋性涡旋、流场辐合加强、水汽通量增加、水汽通量辐合加强 ,并伴有高层较强辐散的情况下。 (4)Q矢量辐合带对暴雨有指示意义 ,尤其是在天气影响系统不明显的情况下 。

The heavy rain process causing mud rock flow calamity in the northwestern Sichuan Basin on 18-20, sept. 2001 is analyzed. The results are obtained as follows: (1) Heavy rain causing mud rock flow is connection with early rain day, intensity of heavy rain, geology, landforms. It is suitable that the forecasting area are divided by geology landforms for the heavy rain causing mud rock flow. (2)The weather influence systems at 500hPa are difference in the early and late period of the heavy rain. (3) The heavy rain is presented under the condition of the strong positive vorticity, convergence, vapor flux convergence in middle and lower troposphere and stronger divergence at upper troposphere. (4) Q vector convergence band has indicative significance for the heavy rain. Specially, Q vector analysis is more beneficial when the weather influence system is not obvious.