山区地形开阔度的分布式模型

 地形开阔度是影响山地辐射平衡及其分量的重要地形因子，是山区散射辐射、地形反射辐射等计算的重要参数。在复杂的地形条件下，地形开阔度的计算很难用数学公式描述。 利用数字高程模型（DEM），全面考虑了坡地自身遮蔽和周围地形相互遮蔽的影响，提出了山区地形开阔度的分布式模型和算法。以1 km×1 km分辨率的DEM数据作为地形的综合反映，计算了起伏地形下中国地形开阔度的空间分布。同时，利用100 m和1 km两个分辨率的DEM数据，从不同DEM分辨率和不同地貌类型两个方面探讨了地形开阔度的空间尺度效应，阐明了区域地形开阔度随地形地貌和空间分辨率的变化规律。所提供的山地开阔度的数据可作为基础地理数据供相关研究应用。

Distributed Modeling of Terrain Opening Extent over Mountainous Terrains

The terrain opening extent (TOE) is the important topography factor that affects on radiation balance and radiation component, and is the significant parameter in calculating diffusion radiation and reflect radiation of surrounding terrain over mountainous terrains. The difficulties in calculating TOE are hardly described by mathematics formula due to complex terrain conditions over mountainous terrain, so it is usually an unknown topography parameter. Based on the Digital Elevation Model (DEM), a new distributed modeling and arithmetic is proposed to calculate TOE over mountainous terrain by taking into account the influences of obstruction caused by sloping grid itself and by surrounding terrain is both discussed. Using this model, the TOE with resolution of 1 km×1 km DEM for the rugged topography of China is calculated. And the topographic and spatial-scaling effects on the TOE were analyzed through two aspects: the different terrain types and different spatial scales of the DEM data. The changing rules of TOE according to the geomorphology and spatial scale were found out. The TOE can be employed as basic geographic data for relevant researches as well.