Long-term variations in oxygen green line emission over Kiso, Japan, from ground photometric observations using continuous wavelet transform

• Published in: Journal of Geophysical Research: Atmospheres 2008-10, Vol.113 (D19), p.n/a
• Main Authors: Das, Uma, Sinha, H. S. S.
• Format: Article
• Language: English
• Subjects: Airglow; Amplitudes; Continuous wavelet transform; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geophysics; Grounds; Interferometers; Mesosphere; Mesospheric airglow; Nocturnal variations; quasi-biennial oscillation; semiannual oscillation
• ISSN: 0148-0227; 2169-897X; 2156-2202; 2169-8996
• DOI: 10.1029/2007JD009516

An analysis of 16 years long ground based photometric data of the oxygen green line (557.7 nm) over a mid latitude station Kiso (35.79°N, 137.63°E) was made using the continuous wavelet transform. This analysis shows the presence of semiannual, annual, and quasi‐biennial variations in the airglow emission, which show interannual as well as nocturnal variations. The semiannual component is present during certain epochs and absent at other times. Also, it is statistically significant at 2000 hours JST (UT+09:00 hrs) and weakens as the night progresses. This variation is similar to the variation seen in wind imaging interferometer (WINDII) satellite data and thermosphere‐ionosphere‐mesosphere‐electrodynamics – global circulation model (TIME‐GCM) model as well. The annual component is present during the entire epoch, but its amplitude shows a minimum during the midnight. In addition, a strong quasi‐biennial component is also seen at 2000 and 0200 hours JST, the amplitude of which exceeds the semiannual component during certain epochs. This component was not detected in earlier studies using the same data. These variations in the oxygen airglow show the effect of tidal dynamics in the mesosphere and lower thermosphere.