Spectral airglow temperature imager (SATI): a ground-based instrument for the monitoring of mesosphere temperature

The spectral airglow temperature imager is a two-channel, Fabry-Perot spectrometer with an annular field of view and a cooled CCD detector. The detected fringe pattern contains spectral information in the radial direction and azimuthal spatial information from the annular field of view. The instrument measures the rotational temperature from the O2 atmospheric (0,1) nightglow emission layer at 94 km and from the Q branch of the OH Meinel (6,2) band emission layer at 87 km. The method for temperature derivation is based on the temperature dependence of the line-emission rates. This dependence allows a determination of the temperature by a least-squares fit of the measured spectrum to a set of synthetic spectra, an approach that minimizes the effect of noise from the sky background and the detector. The spectral airglow temperature imager was developed to meet a need for monitoring the role of the mesosphere in climate variability through long-term observation of the mean temperature and the gravity waves from a single station, as well as large-scale wave perturbations through the use of multiple stations.