大别山地形对降水的增幅作用研究

Study of Ta-Pieh Mountains Terrain on the Precipitation Enhancement

为探索研究大别山山脉地形对降水的增幅作用,利用常规资料、LAPS系统同化资料和中国科学院DEM数据,描述了大别山降水和极端强降水的气候分布,分析了地形对2009年6月29~30日大别山强降水的增幅作用,并利用WRF模式进行地形敏感性试验,最后进行了水汽的辐合雨量和水汽垂直输送增量的计算。研究表明:从气候尺度上看,大别山地区降水与地形密切相关,雨量极值分布有明显的局地性,高海拔地区和西南坡更容易出现强降水。在此次强降水过程中,降水量与海拔高度呈正相关关系,迎风坡上降水随着山高出现陡增。WRF敏感性试验反映了此次强降水分布明显受地形影响,地形雨量增幅较大。从水汽的辐合雨量和水汽垂直输送增量上看,高海拔地区和迎风坡雨量增幅与降水背景场关系不大,而主要来自于山体抬升作用引起的水汽垂直输送增量。

In order to explore the effect of the Ta-pieh mountain range on the increase of precipitation, by using conventional LAPS and DEM data in the Chinese Academy of Sciences, this paper describes the climate distribution of precipitation and extreme precipitation in the Ta-pieh Mountains, analyzes the effect of Ta-pieh Mountains terrain on the precipitation enhancement during June 29 to 30 June of 2009, uses the WRF model to test the terrain sensitivity, and finally calculates the vapor convergence rainfall and vapor vertical transport increment. According to the climate scale, the results show that the precipitation is closely related to the Ta-pieh Mountains terrain, the distribution of extreme rainfall has obvious local characteristics, high altitude areas and the southwest slope are more prone to extreme rainfall. During the precipitation process, the precipitation is positively correlated with the altitude, which rises rapidly with the increase of height on the windward slope. WRF sensitivity test shows that the intensity of the heavy rainfall distribution is obviously affected by the terrain, and the enhancement of the rainfall is large. From the results of the vapor convergence rainfall and vapor vertical transport increment, the enhancements of rainfall in high altitude areas and the windward slope are less linked to precipitation background, which mainly derives from vapor vertical transport increment caused by the uplift of the mountain.