利用MM5中尺度数值模式,针对2004年6月30日成都地区的一次局地大暴雨过程,进行了是否引入加密自动站资料形成模式初值的敏感性试验。结果表明,MM5模式较好地再现了这次强降水过程,初值对预报效果存在不同程度影响。加密自动站资料引入,对降水强度有一定影响,对降水落区有所改善,使各方案模拟的辐合上升运动区范围扩大,相对湿度增大,地面感热与潜热有不同程度增加。初值的差异主要表现在水汽场上。因此,模式初值的改善,特别是水汽场的改善,将对模式降水模拟结果产生较大影响。
A local rainstorm in Chengdu district on 30 June 2004 is simulated by using the MM5 meso-scale numerical model.The sensitivity experiments on the initial values whether including the data of encrypted automatic observation stations or not are made.The results show that the MM5 model possesses better prediction performance.The data of the encrypted automatic observation with initial values have some effects on the prediction.The simulated precipitation intensity is changed and the simulated precipitation area is improved.The simulated convergent ascent areas are improved.The simulated convergent ascent areas by different schemes are enlarged.The relative humidity values area increased.The surface sensitivity flux and the latent heat flux are increased.The difference between the two type initial values appears on the vapor field.The improvement of the initial values,especially those of the vapor field has more3 obvious effect on the simulation results.