Seasonal variations of the nighttime O(1S) and OH (8‐3) airglow intensity at Adelaide, Australia

Abstract

AbstractWe analyze 15 years of atomic oxygen (OI) 558 nm and hydroxyl (OH) (8‐3) 730 nm nightglow emission intensities from heights near 96 and 87 km, respectively, measured using filter photometers at the Buckland Park Field Station (34.6°S, 138.6°E) near Adelaide, Australia. The intensity of both emissions exhibits clear seasonal and interannual periodicities, with annual, semiannual, and quasi‐biennial oscillations, as well as a solar cycle influence. In addition, there is a terannual and 4.1 year component in the OI airglow intensity and both a quasi‐biennial and quasi‐triennial oscillation in the OH intensity. The results are in very good agreement with simultaneous collocated measurements made with an imager, and with global satellite climatologies of OI and OH intensities reported for the Wind Imaging Interferometer instrument. The mean value of the OI annual oscillation intensity is the same as that of the semiannual oscillation at this location to within the experimental uncertainty. The OI annual oscillation maximizes in summer, and the semiannual oscillation maximizes in autumn and spring, with the largest maximum in autumn. The terannual component in the OI nightglow maximizes in early summer, autumn, and spring. The quasi‐biennial oscillation in the OI nightglow takes its first maximum value in autumn 1996, and the 4.1 year period in this emission first maximizes in summer 1998. The OH annual and semiannual oscillation intensities also agree to within the experimental uncertainties and are observed to peak in early winter. The quasi‐biennial and quasi‐triennial oscillations in this emission take their first maximum value in summer 1996.