Solar aureole instrumentation and inversion techniques for aerosol studies: Part 1, system design and calibration

The in-flight calibration of satellite radiometers using ground truth measurements relies on the use of an atmospheric radiative transfer code. The accuracy of the calibration depends largely on the aerosol model used in the radiative transfer codes. In order to improve the calibrations, a camera system has been developed for the determination of the aerosol size distribution, index of refraction, and scattering phase function. In addition, the camera can be used to measure ozone and water vapor content. The camera uses a two dimensional silicon CCD array to image the sun and the solar aureole. A filter wheel provides eight spectral bands from 310 nm to 1045 nm. The camera is mounted on an altitude-azimuth mount for tracking the sun. An external computer allows automatic or manual data acquisition. This paper presents the design and calibration of the camera system. A companion paper presents the data collection and inversion techniques used to retrieve the parameters of interest.