Short-period global atmospheric waves revealed by nightglow observations

The night-time emissions of OH (6–2) and the O₂ Atmospheric System (0–1) have been observed at Maimaga (63.1° N, 129.6° E) during the winters of 2007–2008 and 2008–2009 and revealed steady-frequency atmospheric oscillations near the mesopause at intradiurnal periods longer than about 1.5 h. The Lomb–Scargle method of spectral analysis for unevenly spaced data was applied over the 5-day windows sliding along a series with a 1-day step. The strength of the oscillations and their frequency distribution were found to vary significantly with time. The oscillations at periods longer than about 4 h are always revealed but those shorter than 4 h are detected occasionally. The oscillations of periods shorter then 4 h seem to be affected by macroscale atmospheric dynamical processes but no correlation with polar geomagnetic disturbances was found. Some of the oscillations may be interpreted as the subharmonics of solar tide with numbers up to ∼15.