Influence of Solar and Lunar Tides on the Mesopause Region as Observed in Polar Mesosphere Summer Echoes Characteristics

• Published in: Journal of geophysical research. Atmospheres 2017-10, Vol.122 (19), p.10,369-10,383
• Main Authors: Dalin, P., Kirkwood, S., Pertsev, N., Perminov, V.
• Format: Article
• Language: English
• Subjects: Aerosol layers; Amplitudes; Components; Data; Demodulation; Diurnal variations; Echoes; Geophysics; Gravitation; Gravity; Harmonics; lunar gravitational tides; Lunar tides; Mathematical models; Mesopause; Mesosphere; mesospheric dynamics; Oscillations; Periodicities; Photovoltaic cells; Polar mesosphere; Polar mesosphere summer echoes; Radar; Rotation; Semidiurnal tides; Solar heating; solar migrating thermal tides; Solar rotation; Solar tides; Statistical analysis; Statistical methods; Summer; Tidal amplitude; Tides; Wind speed; Wind velocities
• ISSN: 2169-897X; 2169-8996
• DOI: 10.1002/2017JD026509

Long‐term observations of polar mesosphere summer echoes (PMSE) from 2002 to 2012 are investigated with the aim to statistically study the effects of solar thermal migrating and lunar gravitational tides on aerosol layers and their environment at altitudes 80–90 km. The solar and lunar tidal periodicities are clearly present in PMSE data. For the first time, both amplitudes and phases of solar and lunar tides are estimated using PMSE data from the ESRAD radar located at Esrange (Sweden). The diurnal, semidiurnal, and terdiurnal solar migrating tides show pronounced periodicities in the PMSE strength and wind velocity components. Lunar tides demonstrate clear oscillations in the PMSE strength and wind velocities as well. “canonical” lunar gravitational tides, corresponding to the lunar gravitational potential, produce rather large amplitudes and are comparable to the solar thermal tides, whereas “noncanonical” lunar oscillations have minor effects on PMSE layers, but are still statistically significant. The influence of diurnal/semidiurnal tides and monthly/semimonthly tidal components is studied separately. Our estimations of solar thermal and lunar tidal amplitudes are in good agreement with those of previous model and experimental studies. A new mechanism of quadratic demodulation of the solar semidiurnal and lunar semidiurnal tides is shown to be valid at the summer mesopause and can explain periodical PMSE oscillations due to the lunar synodic semimonthly tide with period of 14.77 days. Two harmonics with periods of 27.0 and 13.5 days supposedly representing the solar rotation cycle are also clearly present in PMSE data. Key Points For the first time, the influence of both solar and lunar tides on PMSE is comprehensively investigated using large statistics Diurnal variations of the PMSE strength can partly be explained by superposition of three main harmonics of the solar tide (24, 12, and 8 h) A new mechanism of quadratic demodulation can explain the lunar synodic semimonthly tide with period of 14.77 days