Skylight VIS-NIR Polarization Radiometer: Design, Calibration, and Measurement

Skylight polarization radiation measurement has important application value in atmospheric remote sensing, aerosol retrieval, and polarization navigation. Traditional instruments like the Cimel CE318, while widely used in AERONET and SONET networks, suffer from limitations, such as long measurement time resolution, limited measurement modes, and incomplete calibration. Addressing these gaps, this article designs and implements a Skylight VIS-NIR Polarization Radiometer (SVNPR) for precise spectral polarization measurements, covering a spectral range of 400-1100 nm. The SVNPR, based on ground-based passive, robust, constant-temperature, and multiscan features, is particularly suited for field deployment. Furthermore, a comprehensive and feasible indoor calibration scheme is proposed, including spectral calibration, radiometric calibration, and polarimetric calibration. Finally, field measurements were conducted, and the experimental results show that the SVNPR can achieve effective and accurate skylight polarization measurements in practical applications. The calibrated instrument showed good consistency with CE318-DP, with mean absolute deviation (MAD) and root mean square error (RMSE) both within 0.005.