基于Landsat 8的川西复杂地形太阳辐射估算研究

山地地表太阳辐射受坡度、坡向及地形遮蔽等影响，导致区域地表所接收的连续分布的太阳辐射量较难测量，而针对山地地表太阳辐射估算已成为目前研究的一个重点。为定量分析山地地表太阳辐射，本文利用Landsat8遥感影像、数字高程模型及气象观测数据计算相关参数，采用已有的太阳直射模型、天空散射模型和周围地形反射模型，综合估算研究区山地地表特定时刻的瞬时太阳辐射，同时根据气象站点获取的逐时太阳辐射和日总辐射量数据对结果进行验证。结果表明:该模型估算的山地瞬时太阳辐射误差均值为13.56 W/m2，日总辐射量误差均值为1.49 MJ/m2，估算值与观测值存在较好的一致性，结果误差小，精度高，参数可靠。山地太阳辐射分布与地形地貌密切相关，总体上阳坡大于阴坡，山脊大于山谷。山区太阳辐射随坡度增大而递减，同时受坡向、植被覆盖度等因素影响，坡面辐射量在一定坡度有略微上升趋势，当坡度大于太阳天顶角时，辐射量下降明显。山区受植被覆盖影响，随着地表植被的增加，地表辐射量呈下降趋势。 

Estimation of Solar Radiation in Complex Topography of Western Sichuan Based on Landsat 8

Due to the influence of slope, aspect and terrain shielding, the continuous distribution of solar radiation received by the mountain surface is difficult to measure, and the estimation of solar radiation on the mountain surface has become a focus of current research. In order to analyze the solar radiation on the mountain surface quantitatively, Landsat8, DEM and meteorological observation data are used to calculate the relevant parameters, and the transient solar radiation at a specific time on the mountain surface of the study area is estimated comprehensively by using the existing direct solar radiation, sky scattering radiation and ambient topographic reflection models. At the same time, the results are verified according to the hourly solar radiation and total daily radiation data obtained from the meteorological station. The results show that the error mean value of mountain instantaneous solar radiation is 13.56 W/m2, and the error mean value of the total daily radiation is 1.49 MJ/m2, There is a good consistency between the estimated value and the observed value. The error is small, the precision is high and the parameters are reliable. The distribution of solar radiation in mountainous areas is closely related to topography. In general, the solar radiation on the sunny slope is larger than that on the shady slope, and the solar radiation on the ridge is larger than that in the valley. The solar radiation in the mountainous area decreases with the increase of slope and is affected by factors such as slope aspect and vegetation coverage. The slope radiation has a slight upward trend at a certain slope, and when the slope is greater than the solar zenith angle, the radiation decreases significantly. Affected by vegetation coverage in mountainous areas, with the increase of surface vegetation, surface radiation decreases.