Translation Characteristics of Orographic Precipitation by using the animation of Radar observed Rainfall and Digital Terrain Model.

本研究的目的是了解地形对暴雨面积或雨强时空分布的影响。研究中使用了雅山、赤城山和雅库什山3个测点的5min间隔雷达资料和5公里网格数字地形模型。通过叠加在三维显示地形上的雷达观测雨量动画来识别雨区的平移特征。在此基础上，将风暴区的转换模式划分为几种情况。在每种情况(或每种降雨类型)下，利用数字地形模型和雷达观测雨量，研究了地形参数与降雨强度的关系。选取高程、坡度和坡向、坡向与雨云移动方向的夹角和距海岸线的距离作为地形参数，分析了这些参数与时均雨强、最大雨强和总雨量的相关性。分析结果表明：1)坡向与雨云移动方向的夹角与距海岸线的距离具有较好的相关性；2)不同的降雨类型，如台风型、低压型、锋面型或雷暴型，地形对暴雨区平移或雨强时空分布的影响是不同的。

The purpose of this study is to understand the effect of orography on translation of storm area or temporal and spatial distribution of rainfall intensity. The 5 min interval radar data observed at 3 sites (Mt Yae, Mt Akagi and Mt Yakushi) and 5km grid Digital Terrain Model are used in this study. The translation characteristics of rainfall area is identified from the animation of radar observed rainfall which is overlaid on the 3-D displayd topography. Based on this analysis, translation pattern of storm area is classified into several cases. In each cases (or each rainfall type), the relationship between the topographic parameters and rainfall intensity is investigated by using the digital terrain model and radar observed rainfall. Elevation, inclination and aspect of a slope, angle between slope aspect and direction of rainfall cloud movement and distance from coastal line are selected as the topographic parameters and correlation between these parameters and time-averaged rainfall intensity, maximum rainfall intensity and total rainfall are examined at each radar cells. The results of this analysis shows that1) angle between slope aspect and direction of rainfall cloud movement and distance from coastal line shows the reasonable correlation between rainfall intensity or time-space distribution.2) orographic effect on translation of storm area or temporal and spatial distribution of rainfall intensity is different in each rainfall type, such as typhoon type, low pressure type, frontal type or thunder storm type.