Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 27, 3225-3235, 2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.
19 Aug 2009
Solar cycle signatures in the NCEP equatorial annual oscillation
H. G. Mayr1, J. G. Mengel2,†, F. T. Huang3, and E. R. Nash2 1NASA Goddard Space Flight Center, Greenbelt, MD, USA
2Science Systems and Applications Inc., Lanham, MD, USA
3University of Maryland, Baltimore, MD, USA
Abstract. Our analysis of temperature and zonal wind data (1958 to 2006) from the National Center for Atmospheric Research (NCAR) reanalysis (Re-1), supplied by the National Centers for Environmental Prediction (NCEP), shows that the hemispherically symmetric 12-month equatorial annual oscillation (EAO) contains spectral signatures with periods around 11 years. Moving windows of 44 years show that, below 20 km, the 11-year modulation of the EAO is phase locked to the solar cycle (SC). The spectral features from the 48-year data record reveal modulation signatures of 9.6 and 12 years, which produce EAO variations that mimic in limited altitude regimes the varying maxima and minima of the 10.7 cm flux solar index. Above 20 km, the spectra also contain modulation signatures with periods around 11 years, but the filtered variations are too irregular to suggest that systematic SC forcing is the principal agent.

Citation: Mayr, H. G., Mengel, J. G., Huang, F. T., and Nash, E. R.: Solar cycle signatures in the NCEP equatorial annual oscillation, Ann. Geophys., 27, 3225-3235,, 2009.
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