精确且已知面积的主光阑对于搭载在气象卫星上的太阳辐照绝对辐射计(SIAR)有着重要作用,其带来的不确定度分量是太阳辐射计测量辐照度不确定度的重要组成部分.有效面积法是一种测量主光阑面积的方法,其通过叠加高斯光束形成一个统一的照度均匀分布的光源区域,利用辐射测量中光阑对光束的限制效应定义主光阑面积.对SIAR 进行简单介绍,主要对有效面积法的测量原理进行理论分析及模拟仿真,提出了具体搭建测量装置的方案,并对主光阑面积进行测量,测量合成不确定度达到8.2 × 10-5 .该测量方法提高了太阳辐照绝对辐射计主光阑面积的测量精度,使得太阳辐照绝对辐射计测量辐照度的标准不确定度从8 × 10-4 提高到6.3 × 10-4 .

For solar irradiance absolute radiometer (SIAR) boarded on meteorological satellites,the main aperture of known area plays an important role.The uncertainty of the main aperture area is at present one of the largest components of the uncertainty in SIAR measurement.The effective area method is a way to measure the main aperture area.It defines the main aperture area based on the aperture of beam- limiting effect in radiometric measurement.Through a superposition of Gaussian beams to generate a known constant irradiance covers the surface of the measured apertures.The ratio of the flux to the irradiance gives the aperture area.We introduce the SIAR,and expound theoretical analysis of the measurement method using Matlab and TracePro software to make simulations.Put forward the specific measurement scheme,and make the uncertainty budget of the measurement device.The combined measurement uncertainty of the main aperture is about 8.2 × 10-5 .This method improves the measurement accuracy of the main aperture,makes the uncertainty of the irradiance measurement about the SIAR from 8 × 10-4 to 6.3 × 10-4 .