Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.490 IF 1.490
  • IF 5-year value: 1.445 IF 5-year
    1.445
  • CiteScore value: 2.9 CiteScore
    2.9
  • SNIP value: 0.789 SNIP 0.789
  • IPP value: 1.48 IPP 1.48
  • SJR value: 0.74 SJR 0.74
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 88 Scimago H
    index 88
  • h5-index value: 21 h5-index 21
Volume 20, issue 12
Ann. Geophys., 20, 2033–2038, 2002
https://doi.org/10.5194/angeo-20-2033-2002
© Author(s) 2002. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 20, 2033–2038, 2002
https://doi.org/10.5194/angeo-20-2033-2002
© Author(s) 2002. This work is distributed under
the Creative Commons Attribution 3.0 License.

  31 Dec 2002

31 Dec 2002

The 16-day variation in tidal amplitudes at Grahamstown (33.3° S, 26.5° E)

S. B. Malinga and L. M. G. Poole S. B. Malinga and L. M. G. Poole
  • Department of Physics and Electronics, Rhodes University, Grahamstown, 6140, South Africa
  • Correspondence to: L. M. G. Poole (g.poole@ru.ac.za)

Abstract. Meteor wind data at Grahamstown (33.3° S, 26.5° E) have been used to study the short-term (planetary scale) variations of the diurnal and semidiurnal tidal amplitudes at ~ 90 km altitude. Wavelet multi-resolution and spectral techniques reveal that planetary periodicities of ~ 10 and ~ 16 days dominate the wave spectrum in the ~ 2–20-day period range. The quasi-16-day oscillation is thought to be related to similar oscillations in the lower atmosphere. Also, there seems to be a link between the winter/equinox 16-day oscillation in the mean flow and that in the semidiurnal tidal amplitudes. It is thought that this is probably due to either the coupling between the normal mode-mean flow interactions and the gravity wave-tidal interactions, or to direct nonlinear interactions between planetary waves and the tide. On the other hand, a comparison of the mean flow and the diurnal tide does not show evidence of correlation. Possible reasons for this disparity are discussed briefly.

Key words. Meteorology and atmospheric dynamics (waves and tides)

Publications Copernicus
Download
Citation