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的平移或降雨强度的时空分布的影响。本研究利用了Yae山、赤城山和Yakushi山3个站点的5 min间隔雷达观测资料和5km栅格数字地形模型。降雨区域的平移特征是通过叠加在三维地形上的雷达观测降水动画来识别的。在此基础上，将风暴区的平动模式划分为几种情况。在每种情况下（或每种降雨类型），利用数字地形模型和雷达观测降雨量研究地形参数与降雨强度之间的关系。选取坡度的高程、倾斜度和坡向、坡向与雨云移动方向的夹角以及与海岸线的距离作为地形参数，并在每个雷达单元检查这些参数与时均降雨强度、最大降雨强度和总降雨量的相关性。分析结果表明：1)坡向与雨云运动方向的夹角与离海岸线的距离在降雨强度或时空分布上表现出合理的相关性。2)不同降雨类型（如台风型、低压型、锋面型或雷暴型）的地形效应对暴雨面积或降雨强度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.