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Volume 51 Supplement 7-8

Special Issue: Dynamics and Structure of the Mesopause Region (DYSMER)

Longitudinal variations in planetary wave activity in the equatorial mesosphere

Abstract

Zonal and meridional winds in the equatorial mesosphere and lower thermosphere (65–98 km) measured at two sites separated by 94° in longitude are used to study the zonal structure of planetary-scale waves. The data were obtained with MF radars located at Pontianak (0°N, 109°E)and Christmas Island (2°N, 157°W). The data at Christmas Island were collected from January 1990 to December 1997 and the observations at Pontianak were made from November 1995 to July 1997. Power spectral techniques are used to study the amplitude and frequency variations of long-period oscillations as a function of height and time. A mean climatology of these variations taken from years 1990–1997 is presented. Strong peaks in zonal and meridional winds are found at tidal periods and for the quasi 2-day wave. Zonal spectra exhibit considerable power at periods of 3–10 days, with transient oscillations with periods near 3.5 day and 6.5 days being especially prominent. The 6.5-day wave is particularly strong during April and September. Examination of the phase differences obtained from cross-spectra between the two stations show that the 6.5-day wave is westward propagating with zonal wavenumber 1, while the 3.5 day wave is eastward propagating with wavenumber 1. The 6.5-day wave is identified as a manifestation of an unstable mode, while the 3.5-day wave is identified as an ultrafast Kelvin wave. There are significant longitudinal variations in the amplitudes and inferred momentum fluxes of the 3.5-day wave, amplitudes being larger in the Asian region than in the central Pacific.

References

  • Andrews, D. G., J. R. Holton, and C. B. Leovy, Middle Atmospheric Dynamics, 489 pp., Academic Press, Orlando, 1987.

    Google Scholar 

  • Avery, S. K., J. P. Avery, T. A. Valentic, S. E. Palo, M. J. Leary, and R. L. Obert, A new meteor echo detection and collection system: Christmas Island mesospheric measurements, Radio Sci., 25, 657–669, 1990.

    Article  Google Scholar 

  • Briggs, B. H., The analysis of spaced sensor records, in Handbook for Map, 13, edited by R. A. Vincent, pp. 166–186, 1984.

  • Burrage, M. D., D. A. Gell, P. B. Hays, A. R. Marshall, D. A. Ortland, W. R. Skinner, S. J. Franke, D. C. Fritts, P. Hoffman, A. H. Manson, C. McLandress, R. Nieciejewski, F. J. Schmidlin, G. G. Shepherd, W. Singer, T. Tsuda, and R. A. Vincent, Validation of mesospheric and lower thermospheric winds from the high resolution Doppler imager, J. Geophys. Res., 101, 10,365–10,392, 1996a.

    Article  Google Scholar 

  • Burrage, M. D., R. A. Vincent, H. G. Mayr, W. R. Skinner, N. F. Arnold, and P. B. Hays, Long-term variability in the equatorial mesosphere and lower thermosphere zonal wind, J. Geophys. Res., 101, 12,847–12,854, 1996b.

    Article  Google Scholar 

  • Canziani, P, O., J. R. Holton, E. F. Fishbein, and L. Froideveaux, Equatorial Kelvin wave variability during 1992 and 1993, J. Geophy. Res., 100, 5193–5202, 1995.

    Article  Google Scholar 

  • Conner, L. N. and S. K. Avery, A three year gravity wave climatology of the mesosphere and lower thermosphere over Kauai, J. Geophys. Res., 101, 4065–4077, 1996.

    Article  Google Scholar 

  • Dunkerton, T. J., A Theory of the mesopause semiannual oscillation, J. Atmos. Sci., 39, 2681–2690, 1982.

    Article  Google Scholar 

  • Eckermann, S. D. and R. A. Vincent, First observations of intraseasonal oscillations in the equatorial mesosphere and lower thermosphere, Geophys. Res. Lett., 21, 265–268, 1994.

    Article  Google Scholar 

  • Eckermann, S. D., D. K. Rajopadhyaya, and R. A. Vincent, Intraseasonal wind variability in the equatorial mesosphere and lower thermosphere: Long term observations for the central Pacific, J. Atmos. Terr. Phys., 59, 603–627, 1997.

    Article  Google Scholar 

  • Fritts, D. C. and T. E. VanZandt, Spectral estimates of gravity wave energy and momentum fluxes. Part I: Energy dissipation, acceleration, and constraints, J. Atmos. Sci., 50, 3685–3694, 1993.

    Article  Google Scholar 

  • Garcia, R. R., T. J. Dunkerton, R. S. Lieberman, and R. A. Vincent, Climatology of the semiannual oscillation of the tropical middle atmosphere, J. Geophys. Res., 102, 26,019–26,032, 1997.

    Article  Google Scholar 

  • Hamilton, K. P., Rocketsonde observations of the mesospheric semiannual oscillation at Kwajalein, Atmos-Oceans., 20, 281–286, 1982.

    Article  Google Scholar 

  • Harris, T. J. and R. A. Vincent, The Quasi-Two-day wave Observed in the Equatorial Middle atmosphere, J. Geophys. Res., 98, 10,481–10,490, 1993.

    Article  Google Scholar 

  • Hirota, I., Equatorial waves in the upper stratosphere and mesosphere in relation to the semiannual oscillation of the zonal wind, J. Atmos. Sci., 35, 714–722, 1978.

    Article  Google Scholar 

  • Hirota, I., Kelvin waves in the equatorial middle atmosphere observed by the Nimbus 5 SCR, J. Atmos. Sci., 36, 217–222, 1979.

    Article  Google Scholar 

  • Hitchman, M. H. and C. B. Leovy, Evolution of the zonal mean state in the equatorial middle atmosphere during October 1978–May 1979, J. Atmos. Sci., 43, 1253–1267, 1986.

    Article  Google Scholar 

  • Hitchman, M. H. and C. B. Leovy, Estimation of the Kelvin wave contribution to the semiannual oscillation, J. Atmos. Sci., 45, 1462–1475, 1988.

    Article  Google Scholar 

  • Isler, J. R. and D. C. Fritts, gravity wave variability and the interaction with the low frequency motions in the lower mesosphere and thermosphere over Hawaii, J. Atmos. Sci., 53, 37–38, 1996.

    Article  Google Scholar 

  • Lieberman, R. S., Intraseasonal variability of high-resolution Doppler imager winds in the equatorial mesosphere and lower thermosphere, J. Geophys. Res., 103, 11,221–11,228, 1998.

    Article  Google Scholar 

  • Lieberman, R. S., M. D. Burrage, D. A. Gell, P. B. Hays, A. R. Marshall, D. A. Ortland, W. R. Skinner, D. Wu, R. A. Vincent, and S. J. Frank, Zonal mean winds in the equatorial mesosphere and lower thermosphere observed by the high resolution Doppler imager, Geophys. Res. Lett., 20, 2849–2852, 1993.

    Article  Google Scholar 

  • Lieberman, R. S. and D. Riggin, High resolution Doppler imager observations of Kelvin waves in the equatorial mesosphere and lower thermosphere, J. Geophys. Res., 102, 26,117–26,129, 1997.

    Article  Google Scholar 

  • Liebmann, B. and H. H. Hendon, Synoptic-scale disturbances near equator, J. Atmos. Sci., 47, 1463–1479, 1990.

    Article  Google Scholar 

  • McLandress, C., G. G. Shepherd, B. H. Solhiem, M. D. Burrage, P. B. Hays, and W. R. Skinner, Combined Mesosphere/Thermosphere winds using WINDII and HRDI data from the Upper Atmospheric Research Satellite, J. Geophys. Res., 101, 10,441–10,453, 1996.

    Article  Google Scholar 

  • Meyer, C. K. and J. M. Forbes, A 6.5-day westward propagating planetary wave: origin and its characteristics, J. Geophys. Res., 102, 26,173–26,178, 1997.

    Article  Google Scholar 

  • Palo, S. E. and S. K. Avery, Mean winds and the semiannual oscillations in the mesosphere and lower thermosphere at the Christmas island, J. Geophys. Res., 98, 20,385–20,400, 1993.

    Article  Google Scholar 

  • Palo, S. E. and S. K. Avery, Observations of the quasi-two-day wave in the middle and lower atmosphere over Christmas Island, J. Geophys. Res., 101, 12,833–12,846, 1996.

    Article  Google Scholar 

  • Palo, S. E., M. E. Hagan, C. E. Meek, R. A. Vincent, M. D. Burrage, C. McLandress, S. J. Franke, W. Ward, R. R. Clark, P. Hofman, R. Johnson, D. Kuerschner, A. H. Manson, D. Murphy, T. Nakamura, Yu. I. Potnyagin, J. E. Salah, R. Schminder, W. Singer, T. Tsuda, T. S. Virdi, and Q. Zhou, An intercomparison between GSWM, UARS and ground-based radar observations: A case study in January 1993, Ann. Geophys., 15, 1123–1141, 1997.

    Article  Google Scholar 

  • Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, Numerical Recipes in C: The Art of Scientific Computing, 2nd Ed., 994 pp., Cambridge University Press, Cambridge, 1992.

    Google Scholar 

  • Riggin, D., D. C. Fritts, T. Tsuda, T. Nakamura, and R. A. Vincent, Radar observations of a 3-day Kelvin wave in the equatorial mesosphere, J. Geophys. Res., 102, 26,141–26,157, 1997.

    Article  Google Scholar 

  • Salby, M. L., The 2-day wave in the middle atmosphere: Observations and theory, J. Geophys. Res., 86, 9654–9664, 1981.

    Article  Google Scholar 

  • Salby, M. L., Survey of planetary-scale traveling waves: The state of theory and observations, Rev. Geophys. Space Phys., 22, 209–236, 1984.

    Article  Google Scholar 

  • Smith, A. K., Longitudinal variability of the mesopause SAO, Geophys. Res. Lett., 24, 1991–1994, 1997.

    Article  Google Scholar 

  • Tsuda, T., S. Fukao, M. Yamamoto, T. Nakamura, M. D. Yamanaka, T. Adachi, H. Hashiguchi, N. Fujioka, M. Tsutsumi, S. Kato, S. W. B. Harijono, T. Sribimawati, B. P. Sitorus, R. B. Yahya, M. Karmini, F. Renggono, B. L. Parapat, W. Djojonegoro, P. Mardio, N. Adikusumah, H. T. Endi, and H. Wirosumarto, A preliminary report on observations of equatorial dynamics in Indonesia with radars and radiosondes, J. Meteor. Soc. Japan., 73, 393–406, 1995.

    Google Scholar 

  • Vincent, R. A., Long-period motions in the equatorial mesosphere, J. Atmos. Terr. Phys., 55, 1067–1080, 1993.

    Article  Google Scholar 

  • Vincent, R. A. and D. Lesicar, Dynamics of the equatorial mesosphere: First results with a new generation partial reflection radar, Geophys. Res. Lett., 18, 825–828, 1991.

    Article  Google Scholar 

  • Vincent, R. A., S. Kovalam, D. C. Fritts, and J. R. Isler, Long-term MF radar observations of solar tides in the low-latitude mesosphere: Interannual variability and comparisons with the GSWM, J. Geophys. Res., 103, 8667–8683, 1998.

    Article  Google Scholar 

  • Wu, D. L., P. B. Hays, W. R. Skinner, A. R. Marshall, M. D. Burrage, R. S. Lieberman, and D. A. Ortland, Observations of the quasi 2-day wave from the High Resolution Doppler Imager on UARS, Geophys. Res. Lett., 20, 2853–2856, 1993.

    Article  Google Scholar 

  • Wu, D. L., P. B. Hays, and W. R. Skinner, Observations of the 5-day waves in the mesosphere and lower thermosphere, Geophys. Res. Lett., 21, 2733–2736, 1994.

    Article  Google Scholar 

  • Yoshida, S., T. Tsuda, A. Shimizu, and T. Nakamura, Seasonal variations of 3.03.8-day ultra-fast Kelvin waves observed with a meteor radar and radiosondes in Indonesia, Earth, Planet. Sci., 1998 (submitted).

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Kovalam, S., Vincent, R.A., Reid, I.M. et al. Longitudinal variations in planetary wave activity in the equatorial mesosphere. Earth Planet Sp 51, 665–674 (1999). https://doi.org/10.1186/BF03353224

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Keywords

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