地形对门头沟一次大暴雨动力作用的数值研究  

Numerical simulation of the dynamic effect of the orography on a Mentougou severe torrential rain event

作　　者：盛春岩[1] 高守亭[2] 史玉光[1] 

机构地区：[1]山东省气象科学研究所,济南250031 [2]中国科学院大气物理研究所云降水物理与强风暴实验室,北京100029

出　　处：《气象学报》2012年第1期65-77,共13页Acta Meteorologica Sinica

基　　金：公益性行业(气象)科研专项项目"黄渤海高影响天气预报中的关键技术研究"(GYHY201106006);山东省超级计算科技专项项目"精细化集合数值天气预报平台"

摘　　要：2002年6月24—25日,北京门头沟附近发生了一次大暴雨过程。为探讨地形在本次过程中的动力作用,采用美国俄克拉荷马大学风暴分析预测中心开发的ARPS模式,对大暴雨过程进行了数值试验。控制试验采用27、9 km双重单向嵌套网格,网格覆盖范围约为3000 km×3000 km、900 km×900 km。两层网格均采用全物理过程,使用的都是全球30″的地形资料。在控制试验的基础上,进行了3组敏感性试验:第1组试验采用干过程模拟,即不考虑凝结潜热的作用;第2组试验将地形整体向东/西平移1°;第3组试验是将门头沟西部的局地地形抠除一部分。试验结果表明,在不考虑凝结潜热作用时,东南风气流仍然可以爬升到2 km以上,超过了大气的抬升凝结高度,证实了地形的动力作用是本次大暴雨的触发机制;将地形向东/西平移1°后,由于大气的对流稳定度发生了改变,模拟的降水强度和落区也发生了变化,表明山坡和山顶的对流不稳定大气是导致本次大暴雨的必要条件;抠除局地地形后,模拟的降水量也发生了不同程度的改变,再次证明大暴雨是在多尺度地形以及一定的天气系统配置下产生的。On 24-25 June 2002,a torrential rain event occurred in Beijing near Mentougou,which is regarded as a typical orographic torrential rain event under the eastern flow in the boundary.In order to study the dynamic effect of the orography in this event,numerical simulation is conducted with the Advanced Regional Prediction System（ARPS）.Control experiment two-domain one-way nested grids with the respective horizontal resolutions of 27 and 9 km,and covers squared domains of 3000×3000 and 900×900 km2,respectively.Both domains use the full physics mode of the ARPS and the terrain data are created from a 30-second global terrain data base for the two domains.Three sets of sensitive experiments are conducted for comparison with the control experiment,the first one is dry simulation,that is,no latent heat is considered in the simulation;in the second one,the orographies,as a whole,are moved 1 degree easterly and westerly,respectively,and in the third one,parts of the orography in the southwest of Beijing near Mentougou are removed.The results show that the southeasterly airflow from the Bohai Sea is able to climb to the height of 2 km,which is over the LFC,testifying that the dynamic effect of the orography is the trigger mechanism in this torrential rain event.The convective instability of the air changes when moving the orography,as a result,the location and intensity of the simulated rainfall changes.This result shows that the convective instability of the air on the slope and over the mountain is necessary for the torrential rain to occur.The fact that the simulated rainfall changes as well after removing parts of the orography verifies that the torrential rain is caused under the effect of the multi-scale orography and the suitable weather situation.

关 键 词：大暴雨 地形 动力作用 数值模拟 

分 类 号：P458.121.1[天文地球—大气科学及气象学] P456.7