中文摘要：

基于区域暴雨数值预报模式AREM,针对2003年8月发生在四川盆地西部的多次局地强暴雨过程,通过数值试验,讨论了川西暴雨对初始水汽条件的高度敏感性,揭示了川西暴雨过程独特的局地水汽循环特征。初始水汽条件不仅决定着暴雨的强度,还对最大降水发生时间产生明显影响,从而决定模式对降水日变化的模拟效果。局地初始水汽偏大,不仅导致24小时降水总量的迅速增加,甚至空报暴雨,还使得主要降水时段明显提前,使夜雨变为昼雨。局地初始水汽减少不仅会显著减小降水量,甚至会致使暴雨消失,还会使主要降水时段滞后。

英文摘要：

By using a regional model named AREM （Advanced Regional Eta-coordinate Model）,which was developed by the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamic,Institute of Atmospheric Physics,Chinese Academy of Sciences,several local heavy rainfall events happening over the western Sichuan basin during August 2003 are simulated and analyzed. The results indicate that the initial local water vapor condition is crucial to the happening and evolution of heavy rainfall events over the western Sichuan basin. Both the intensity of heavy rainfall and the time of maximum precipitation are highly sensitive to the initial condition of local water vapor. An increase of initial local water vapor would not only increase the 24-hour accumulated precipitation amount,but also lead to the main rainfall events happening earlier,resulting in a day-time rather than nocturnal rainfall events. Correspondingly,a decrease of initial water vapor would delay the maximum precipitation time and decrease the total precipitation amount.