A heavy rainstorm on 17 August 2007 in Shandong Province was studied on the mesoscale char- acters by the data of conventional and AWS observations, satellite, Doppler radar, lightning location in- strument and WRF simulation. And the sensitivity experiment of numerical model was carried out to inves- tigate the influence of topography. The results are as follows. The heavy rainstorm was caused by the K-H instability, wind shear and vortex. Meanwhile, terrain played an important role in the location and intensi- ty of rainstorm, which brought more rainfall and made heavy rain located in the further south area. The numerical simulation comparison test was worked between the two similar rain processes. The result shows that there are more obviously consistences in many ways, including rainfall area, central intensity and distributions except the intensity of heavy rainfall. The terrain has a stronger effect to the heavy rain- fall. The wind shear caused by terrain made stronger vapor convergence and vertical velocity. What ~smore, the terrain also affected the distribution of cloud vapor and rain vapor. As a result, the favorable circulation and terrain are the important factors to produce the heavy rainstorm.%利用常规资料、区域自动站、气象卫星、多普勒天气雷达、闪电定位资料以及中尺度数值模式WRF，对2007年8月16和17日在山东省新泰市发生的大暴雨天气过程进行分析，并针对中尺度地形对暴雨的影响进行了敏感性试验。研究发现，此次大暴雨发生于副热带高压边缘切变线附近，与速度不连续造成的K—H不稳定而引起的中小涡旋有密切关系。鲁中山脉地形对大暴雨中心的强度和落区有较大影响，在对流层低层产生明显的地形性切变线，加强了偏南暖湿气流的辐合，使大暴雨强度更大，位置更加偏南。对强弱两次相似降水过程进行数值模拟对比试验发现，鲁中山脉地形对两次过程的降水分布、中心强度和落区等影响较为一致，但是对不同强度降雨增幅的影响差异较大，地形对强降雨的增幅作用更加明显。进一步研究表明，地形的抬升作用，造成暴雨区低层辐合加强和垂直速度增强，更有利于不稳定能量积累和水汽的辐合，同时山脉地形在一定程度上还对大气中云水和雨水的分布有较大影响。副热带高压边缘有利的环境背景条件和地形的共同作用是山东局地大暴雨产生和维持的主要物理机制。
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