Ground-based airglow imaging interferometer. Part 2: forward model and inverse method.

The ground-based airglow imaging interferometer (GBAII) observes the nighttime airglow of the O2(0-1) 867.7 nm line, peaked at 94 km altitude, to measure the upper atmospheric wind and temperature field. Its forward model, a code package in interactive data language (IDL), is developed to simulate the expected imaging interference fringes. It includes eight modules to simulate the light source, the atmospheric radiation transmission, the wide-angle Michelson interferometer, the interference filter, the optical system decay function, the responsivity, the imaging CCD, and the noises. The inverse method is also developed for obtaining the rest phase calibration, temperature, and wind. By means of both theoretical tools, we carry out a comparison of theoretical results with a field observation case. The apparent quantities J(1-p) from the forward model has the deviation of 1.5%-2.5% compared with that from the observation image. The temperature falls mainly in the range of 167-196 K with the precision of 2 K. The zonal and meridional winds are mainly in the region of 5.1 to 46.5 m/s and 12.5 to 48.3 m/s respectively, with errors of 13.2 to 21.5 m/s. The consistent trends between the observation results and standard models (MSISE90 and HWM93) suggest that the forward model and inverse method are suitable for GBAII.

Ground-based airglow imaging interferometer. Part 1: instrument and observation.

A ground-based airglow imaging interferometer (GBAII) is proposed to measure simultaneously the temperature and wind in the mesopause region by using airglow emissions of the O2(0-1) band. Since it employs a wide angle Michelson interferometer with a large air gap, combined with the rotational temperature measurement, both the phase and spectral information can be obtained from the imaging results. Based on the optimization and calibrations for the optical system in the laboratory, we developed and assembled a prototype of a GBAII, and carried out one observation at the observatory of Xi'an University of Technology on 12 June 2012. The observed temperatures fall mainly on the range of 167-196 K, while both the zonal and meridional winds faintly show the feature of half-day oscillation. The consistent trends between the observation results and the standard atmospheric models suggest that the GBAII has achieved our basic design goals.