Retrieving nighttime aerosol optical depth using combined measurements of satellite low light channels and ground-based integrating spheres

The aerosol optical depth, as an aerosol optical property, is a key physical quantity used to characterize the degree of atmospheric turbidity. The radiance of the integrating sphere light source after radiometric calibration is relatively stable. Compared with the original use of city lights to invert the night-time aerosol optical depth (AOD), the use of the integrating sphere can effectively reduce the change of the emission source and improve the inversion accuracy. A model to retrieve night-time AOD based on combined measurements of satellite low light channels and ground-based integrating spheres was established by the night-time artificial observation experiment in the Dunhuang radiation correction field (DRCF) for 38 consecutive days from October to November 2018. After excluding cloud pollution and moonlight pollution, the calculated results are compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) data and the Visible/Infrared Imaging Radiometer Suite (VIIRS) night-time aerosol data. The average root mean square error of the processed data is 0.11 and 0.23, and the correlation coefficient reaches 0.85 and 0.46, respectively. The experimental results preliminarily show that the retrieval AOD is in good agreement with the satellite data, and it is feasible to retrieve AOD based on combined measurements of satellite low light channels and ground-based integrating spheres.