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  • Article
  • Open Access

Observation of low frequency Kelvin waves in the mesosphere

Earth, Planets and Space201451:BF03353222

  • Received: 4 August 1998
  • Accepted: 12 February 1999
  • Published:


This paper presents evidence for a quasi-stationary Kelvin wave of zonal wavenumber 1 that is forced in situ in the upper mesosphere and propagates upward from there. Although large scale quasi-stationary longitudinal variations are common in the mesopause equatorial winds, these variations often do not have a structure associated with a vertically propagating mode. However, during the periods of easterly winds that occur near the equinoxes in association with the mesopause semi-annual oscillation (MSAO), a Kelvin wave propagates away from the presumed altitude of forcing. The momentum transport by the Kelvin wave is small and does not make a significant contribution to the SAO wind evolution.


  • Gravity Wave
  • Zonal Wind
  • Meridional Wind
  • Easterly Wind
  • Lower Thermosphere