FY-4A地表太阳入射辐射产品在山西高原的适用性研究

Applicability of FY-4A Surface Solar Irradiance Products in the Loess Plateau of Shanxi

以山西高原为研究区域,利用区域内3个国家级气象站的逐分钟辐射观测数据,对FY-4A的地表太阳入射辐射产品质量进行对比检验。结果表明:该产品与地面观测数据的相关性很高,能够较好地反映气象因素变化对太阳辐射的影响;但总辐照度数值总体偏高,相对误差随地面观测总辐照度的升高而降低,早晚误差大,中午误差小;3个站横向对比来看,年总辐射曝辐量越高,相对误差越小;由于FY-4A地表太阳入射辐射反演算法中太阳天顶角的临界值设为70°,导致全年白天无观测时次约占1/3,且冬季多于夏季,使得冬季的月总辐射曝辐量偏低而夏季偏高。FY-4A地表太阳入射辐射的上述特点基本都源自其反演算法或参数设置,因此具有普适性;由于相对误差呈现出较强的规律性,使得下一步对该产品进行订正、大幅降低误差水平成为可能。

In this paper,the Loess Plateau of Shanxi was selected as the research area,and the quality of FY-4A surface solar irradiance(SSI)was comparatively tested by using the minutely global irradiance data of three national meteorological stations in the region.The results show that SSI is highly correlated with ground observation data in Loess Plateau of Shanxi,which can better reflect the influence of meteorological factors on solar radiation.The global irradiance is generally high,and the relative error decreases with the increase of the global irradiance observed on the ground.The morning and evening errors are large but the noon errors are small.From the transverse comparison of Datong,Taiyuan and Houma stations,the higher the annual global radiation exposure,the smaller the relative errors.The critical value of sunset zenith angle is set at 70°in FY-4A SSI algorithm,resulting in about 1/3 of the whole year’s non observed time in daytime.The total radiation exposured in winter is lower than that in summer,which makes the monthly global radiation exposure lower in winter but higher in summer.The above characteristics of SSI are basically derived from its algorithm or parameter settings,so it has universality.Due to the strong regularity of relative errors,it is possible to revise the data and reduce the error level substantially in the next step.