中文摘要：

利用DEM分析方法为起伏地形下太阳辐射模拟提供了条件。然而DEM的尺度效应对太阳辐射模拟产生很大的影响。本文以黄土丘陵和秦岭高山为实验样区．以一系列不同分辨率的DEM，模拟日、月及年总天文辐射，比较其误差大小及地形分析的差异。实验结果显示．随着DEM栅格分辨率的降低，天文辐射逐渐增大；当栅格分辨率大于地面相对高差时，模拟的天文辐射基本稳定，坡向、坡度等地形因子对辐射的再分配作用已不显著。黄土丘陵区，当DEM分辨率接近1000m时．天文辐射年总量的相对误差为22％．超过该区域一个冬季的天文辐射量。秦岭山区地表起伏大．误差较黄土丘陵地区小．最大相对误差为17．8％。总之，地表起伏越小，DEM栅格分辨率对太阳辐射模拟的影响越大．

英文摘要：

The development of digital terrain analysis based on DEM is helpful for the simulation of solar radiation in rugged area. However the effect of DEM scale causes great uncertainty to the simulation. Taking loess hilly area and Qingling Mountain as test area, this paper studies the relationship between simulated astronomic radiation and DEM resolution through simulating daily, monthly and yearly astronomic radiation based on a serial of DEMs with different resolutions. The experimental result shows that simulated astronomic radiation increases gradually with the decrease of DEM resolution. When DEM grid cell size is greater than the relative heights of the test area, the radiation simulated is stable and the terrain factors such as slope gradient and aspect do not affect on the redistribution of solar radiation any more. In loess hilly area, when DEM grid cell sizes close to 1 000m the relative error of the annual astronomic radiation is about 22%, exceeding the winter＇s radiation in this area. In Qingling mountainous area, errors are relative small and the maximum relative error is 17.8%. In a word, the impacts of DEM resolution on the simulation of the solar radiation are much greater in hilly area than in the mountainous area.