太阳辐射计的衍射效应修正

太阳辐射测量是研究太阳活动与地球气候演变的重要方式之一,对人类社会的可持续发展具有重要意义。衍射效应作为测量过程中系统误差的主要来源之一,有必要进行精确的修正,从而提高测量数据的精度。首先,对衍射效应理论进行研究,从Kirchhoff衍射理论出发,在高斯光学近似下,逐步确定点与点,点与面,面与面之间的能量传输关系,推导出了衍射效应的一般公式;接着,根据衍射效应的渐近性质,得到了一种简化的计算方法;然后,用简化的方法计算太阳辐照绝对辐射计(SIAR)的衍射效应以及衍射修正因子,最后,根据衍射修正结果,计算相对于世界辐射基准(WRR)的定标系数。结果显示:SIAR的衍射效应以及衍射修正因子分别约为1.002 742和0.997 265。经过衍射修正后,SIAR对WRR的定标系数更接近于1,表明衍射修正降低了系统误差,提高了辐射测量的准确度。

Diffraction effect correction of solar radiometer

Solar radiation measurement is one of the important way to study solar activity and evolution of Earth's climate, which is of great significance to the sustainable development of human society. As one of the main sources of systematic errors in the measurement, diffraction effect must be accurately corrected so as to improve the reliability of the measurement data. China has little research on the diffraction effects in solar radiometers, and there are currently no related corrections. With the increase demand of the accuracy of solar radiation measurements, it is necessary to systematically study the diffraction effect. Firstly, the diffraction effect theory is studied. According to the Kirchhoff diffraction theory as well as the Gaussian optical approximation, the energy transfer relations between points and points, points and faces, and between faces is gradually determined, and the general formula of diffraction effect is derived. Then a simplified calculation method is obtained according to the asymptotic property of the diffraction effect. The diffraction effect of the Solar Irradiation Absolute Radiometer (SIAR) and the diffraction correction factor are then calculated through a simplified method. Finally, based on the diffraction correction results, the scaling factor relative to the World Radiation Reference (WRR) is calculated. As a result, the diffraction effects and diffraction correction factors of SIAR are about 1.002 742 and 0.997 225, respectively. In addition, the calibration coefficient of SIAR for WRR is closer to 1, indicating that the diffraction correction reduces the systematic error and improves the accuracy of the radiation measurement.