基于DEM的复杂地形下太阳散射辐射分布式模拟——以贵州高原为例

Study on Distributed Simulation of Diffuse Solar Radiation over Complex Terrains Based on DEM——Taking Guizhou Plateau for Example

由于坡度、坡向和地形之间相互遮蔽等局地地形因子的影响,确定实际复杂地形下太阳散射辐射是比较困难的。本文在前人研究的基础上,对以前的模型进行了一些改进,考虑了坡度、坡向和地形相互遮蔽作用对复杂地形下天文辐射的影响,基于数字高程模型(DEM)数据,研制了以复杂地形下天文辐射为起始数据的复杂地形下太阳散射辐射的分布式模型,在模型中还考虑了散射辐射的各向异性。以地形复杂的贵州高原为例,应用100 m×100 m分辨率的DEM数据及气象站常规观测气象资料,计算了贵州高原复杂地形下各月及年的太阳散射辐射精细空间分布。结果表明:(1)局地地形因子(如坡度、坡向和地形遮蔽)对贵州高原复杂地形下太阳散射辐射的空间分布影响较大,随着地形的起伏变化,太阳散射辐射的空间分布明显不同,纬向分布特征不明显。(2)对于太阳散射辐射而言,地形对其的影响仍然很大,在太阳散射辐射计算时也是不容忽视的。

The diffuse solar radiation （DSR） is the elements of global solar radiation. Due to the influence of local terrain factors such as slope, aspect and terrain inter shielding, it is very difficult to calculate DSR over complex terrains（CT）. The previous models have been improved in this paper on the basis of past studies. The influence of slope, aspect, and terrain inter shielding on astronomical solar radiation over CT is considered, a distributed model, which is based on astronomical solar radiation over CT and diffuse radiation＇s anisotropism, for calculating DSR quantities over CT is developed. Using this model, the elaborate distribution of DSR with resolution of 100 m× 100 m by a DEM and meteorological observation data in the Guizhou Plateau are generated. The results are as follows： （1） The influence of local terrain factors as the slope, aspect and terrain inter-shielding on DSR is great, so that DSR＇s elaborate spatial distribution has obvious terrain distributing feature over CT in Guizhou Plateau. The spatial distribution of DSR is obvious dissimilarity with hypsography, and the zonal distributing character is not evident. （2） For DSR, the effect of topographical factors should not be disregarded.