Articles | Volume 35, issue 5
Ann. Geophys., 35, 1023–1032, 2017
Ann. Geophys., 35, 1023–1032, 2017

Regular paper 31 Aug 2017

Regular paper | 31 Aug 2017

Effects of the planetary waves on the MLT airglow

Fabio Egito1, Hisao Takahashi2, and Yasunobu Miyoshi3 Fabio Egito et al.
  • 1Centro Multidisciplinar de Bom Jesus da Lapa, Universidade Federal do Oeste da Bahia, Bom Jesus da Lapa, 47600-000, Brazil
  • 2Aeronomy Division, National Institute for Space Research, São José dos Campos, 12227-010, Brazil
  • 3Department of Earth and Planetary Sciences, Kyushu University, 744 Motooka Nishi-ku Fukuoka, 819-0395, Japan

Abstract. The planetary-wave-induced airglow variability in the mesosphere and lower thermosphere (MLT) is investigated using simulations with the general circulation model (GCM) of Kyushu University. The model capabilities enable us to simulate the MLT OI557.7 nm, O2b(0–1), and OH(6–2) emissions. The simulations were performed for the lower-boundary meteorological conditions of 2005. The spectral analysis reveals that at middle latitudes, oscillations of the emission rates with the period of 2–20 days appear throughout the year. The 2-day oscillations are prominent in the summer and the 5-, 10-, and 16-day oscillations dominate from the autumn to spring equinoxes. The maximal amplitude of the variations induced by the planetary waves was 34 % in OI557.7 nm, 17 % in O2b(0–1), and 8 % in OH(6–2). The results were compared to those observed in the middle latitudes. The GCM simulations also enabled us to investigate vertical transport processes and their effects on the emission layers. The vertical transport of atomic oxygen exhibits similar periodic variations to those observed in the emission layers induced by the planetary waves. The results also show that the vertical advection of atomic oxygen due to the wave motion is an important factor in the signatures of the planetary waves in the emission rates.