天文辐射空间分布与尺度效应研究

Spatial Distribution of Extraterrestrial Solar Radiation and Its Spatial Scale Effect on Rugged Terrains

天文辐射是地表实际入射太阳辐射的基础背景,也是辐射计算、太阳能资源评估和农业生产潜力估算等方面的重要天文参量。本文基于分辨率为30 m的福建省数字高程模型,使用MATLAB软件提供的并行计算框架模拟了起伏地形下福建省天文辐射空间分布,定量地分析了坡度坡向对天文辐射分布的影响规律,同时探讨数字高程模型对天文辐射产生的空间尺度效应。结果表明:福建省年天文辐射量大部分处于10 000~13 000 MJ/m^2,呈现东南沿海向中西部递减的分布特征;不同季节的天文辐射分布受纬度和坡度坡向的影响具有明显的差异性,呈现季节分布的不对称性;不同坡度和坡向对天文辐射的影响与福建省总体上西北高东南低地势特征相吻合,天文辐射量随坡度增大而减小,东、东南和南坡向是天文辐射分布较集中的区域,总体上呈现山脊多、山谷少、阳坡多、阴坡少的地域差异性;数字高程模型的空间尺度效应在起伏较大的福建中西部丘陵地貌表现更加明显,该区域的天文辐射对分辨率的变化更加敏感。

The Extraterrestrial Solar Radiation （ESR） is the basis of surface solar irradiance, and it is also an important astronomical parameter for calculating solar radiation, assessing solar energy resource and for estimation of agricultural potential productivity. Based on Digital Elevation Model （DEM） data of Fujian Province with a resolution of 30 meters, the spatial distribution of ESR over rugged terrains of Fujian Province was calculated by using parallel computing framework of MATLAB software. Then, the influences of slopes and aspects on the distribution of ESR were quantitatively analyzed. Finally, the spatial scale effects of DEM on ESR were discussed. The results clearly depict that the latitude and complex landforms profoundly disrupt the zonal distribution of ESR in Fujian Province. The terrain factors have more significant effects on the magnitude of ESR compared with the latitude. Annual ESR of Fujian Province was mainly at 10 000-13 000 MJ/m2 and presented a decrease trend from Southeast coastal areas to the Midwestem areas. As affected by the slopes and aspects, the ESR over seasons showed characteristics of differences and dissymmetry. The screening impact of topography was higher on spatial distribution of ESR in winter and considerably low in summer. The total amount of ESR in spring was larger than that in autumn. The influences of different slopes and aspects on the distribution of ESR were consistent with the terrain characteristics of Fujian Province, which is high in the northwest and low in the southeast. The ESR was depleted obviously along with the increase of the slope. The ESR was mainly concentrated in the east, southeast and south. The impact of topographic feature was significant, the ESR in the chine was bigger than the one in the valley and the one in the sunny slope is more than that in the shady slope. Meanwhile, the effect of spatial scale of the DEM was obvious. The ESR of Hills of Midwestern Fujian Province was more sensitive to changes in resolution.