激光点阵扫描法绝对定标太阳辐射计直射通道研究

利用可调谐激光器作为光源，以溯源于低温绝对辐射计的标准传递探测器作为激光束功率测量探测器，采用激光点阵扫描方法在太阳辐射计有效孔径光阑面形成均匀照度场，精确测量太阳辐射计870 nm无偏直射通道中心波长处绝对辐照度响应度。利用灯-单色仪系统扫描获得该通道相对光谱辐照度响应度，最终在实验室条件下获得该通道绝对光谱辐照度响应度，联合大气层外太阳照度谱数据通道内积分得到该通道大气层外响应常数V₀值，与NASA的GSFC中心的2009年定标结果差异仅为3.75%，定标不确定度达到2.06%，验证了这一新技术的原理可行性。

Research on Absolute Calibration of Sun Channel of Sun Photometer Using Laser Raster Scanning Method

In the present paper, a new calibration method of absolute spectral irradiance responsivity of sun channel of sun photometer was developed. A tunable laser was used as source and a standard tranfer detector, calibrated against cryogenic absolute radiometer, was used to measure laser beam power. By raster scanning of a single collimated laser beam to generate the uniform irradiance field at the plane of effective aperture stop of sun photometer, the absolute irradiance responsivity of center wavelength of the 870 nm unpolarized sun channels of sun photometer was obtained accurately. The relative spectral irradiance responsivity of corresponding channel was obtained by using lamp-monochromator system and then used to acquire the absolute spectral irradiance responsivity in the laboratory. On the basis of the above results, the top-of-the-atmosphere responsive constant V0 was obtained by integration with extraterrestrial solar spectral irradiance data. Comparing the calibration result with that from GSFC, NASA in 2009, the difference is only 3.75%. In the last, the uncertainties of calibration were evaluated and reached to 2.06%. The principle feasibility of the new method was validated.