四川盆地夏季降水日变化的数值模拟  

Numerical Simulation of Diurnal Variation of Summer Precipitation in Sichuan Basin

作　　者：沈沛丰[1] 张耀存[1] 

机构地区：[1]南京大学大气科学学院,江苏南京210093

出　　处：《高原气象》2011年第4期860-868,共9页Plateau Meteorology

基　　金：国家自然科学基金项目(40805041)资助

摘　　要：利用区域气候模式RegCM3对1991-2004年四川盆地夏季降水进行了数值模拟,通过模拟结果和NCEP/NCAR再分析资料的对比,评估了模式对四川盆地夏季"夜雨"现象的模拟能力。结果表明,RegCM3模式能较好地模拟出四川盆地夏季降水的空间分布和日变化规律,四川盆地夏季"夜雨"现象的形成与该地区的地形分布有密切关系。夏季四川盆地上空850hPa高度上存在一气旋性辐合中心,低层偏东风进入盆地后受西侧大地形阻挡,辐合抬升,午后盆地内中低层的温度和湿度逐渐升高,使得大气层结不稳定加强,对流活动得到发展,并在夜间达到最强,从而形成四川盆地的"夜雨"现象。A regional climate model（RegCM3） has been applied to simulate the summer precipitation in Sichuan basin during 1991-2004.The station rain-gauge data and NCEP/NCAR reanalysis data are used to evaluate the performance of the model to simulate the diurnal cycle of precipitation,especially the formation of mid-night maximum rainfall.The results show that the RegCM3 can simulate well the spatial distribution and diurnal variation of averaged precipitation in Sichuan basin.The orography forcing is related to the formation of mid-night maximum rainfall.The low-level eastly wind encounters the mountain slopes on the west side of the basin and a convergence center appears on 850 hPa in summer.The low-level temperature and humidity gradually increase at afternoon,which leads to the reinforcement of the unstable layer.In the mean time,the convective activities are enhanced,and reach their maximum at night,which finally results in the mid-night maximum rainfall.

关 键 词：四川盆地 降水日变化 数值模拟 RegCM模式 

分 类 号：P426.633[天文地球—大气科学及气象学]