• An, S-I., , and B. Wang, 2001: Mechanisms of locking of the El Niño and La Niña mature phases to boreal winter. J. Climate, 14 , 21642176.

    • Search Google Scholar
    • Export Citation
  • An, S-I., , and F-F. Jin, 2004: Nonlinearity and asymmetry of ENSO. J. Climate, 17 , 23992412.

  • Blackadar, A K., 1962: The vertical distribution of wind and turbulent exchange in a neutral atmosphere. J. Geophys. Res., 67 , 30953102.

    • Search Google Scholar
    • Export Citation
  • Businger, J A., , J C. Wyngard, , Y. Izumi, , and E F. Bradley, 1971: Flux profile relationship in the atmospheric surface layer. J. Atmos. Sci., 28 , 181189.

    • Search Google Scholar
    • Export Citation
  • Cane, M A., , and S E. Zebiak, 1985: A theory for El Niño and the Southern Oscillation. Science, 228 , 10841087.

  • Chakraborty, D R., , and N K. Agarwal, 1996: Role of triad kinetic energy interactions for maintenance of upper tropospheric low frequency waves during summer monsoon 1998. Adv. Atmos. Sci., 13 , 91102.

    • Search Google Scholar
    • Export Citation
  • Hayashi, Y., 1980: Estimation of nonlinear energy transfer spectra by the cross-spectral method. J. Atmos. Sci., 37 , 299307.

  • Kim, K-Y., 2002: Investigation of ENSO variability using cyclostationary EOFs of observational data. Meteor. Atmos. Phys., 81 , 149168.

    • Search Google Scholar
    • Export Citation
  • Krishnamurti, T N., , H S. Bedi, , and V M. Hardiker, 1998: An Introduction to Global Spectral Modeling. Oxford University Press, 253 pp.

    • Search Google Scholar
    • Export Citation
  • Krishnamurti, T N., , D. Bachiochi, , T. Larow, , B. Jha, , M. Tewari, , D R. Chakraborty, , R. Correa-Torres, , and D. Oosterhof, 2000: Coupled atmosphere–ocean modeling of the El Niño of 1997–98. J. Climate, 13 , 24282459.

    • Search Google Scholar
    • Export Citation
  • Krishnamurti, T N., , D R. Chakraborty, , N. Cubukcu, , L. Stefanova, , and T. S. V. Vijaya Kumar, 2003: A mechanism of the Madden–Julian Oscillation based on interactions in the frequency domain. Quart. J. Roy. Meteor. Soc., 129 , 25592590.

    • Search Google Scholar
    • Export Citation
  • Louis, J F., 1979: A parametric model of vertical eddy fluxes in the atmosphere. Bound.-Layer Meteor., 17 , 187202.

  • Neelin, J D., , F-F. Jin, , and H-H. Syu, 2000: Variations in ENSO phase-locking. J. Climate, 13 , 25702590.

  • Philander, S. G. H., , T. Yamagata, , and R C. Pacanowski, 1984: Unstable air–sea interactions in the Tropics. J. Atmos. Sci., 41 , 604613.

    • Search Google Scholar
    • Export Citation
  • Sheng, J., , and Y. Hayashi, 1990a: Observed and simulated energy cycles in the frequency domain. J. Atmos. Sci., 47 , 12431254.

  • Sheng, J., , and Y. Hayashi, 1990b: Estimation of atmospheric energetics in the frequency in the FGGE year. J. Atmos. Sci., 47 , 12551268.

    • Search Google Scholar
    • Export Citation
  • Ueda, H., 2002: Equatorial monsoon system as regulation for a dipole mode in the Indian Ocean. Pap. Meteor. Geophys., 51 , 147154.

  • Wang, B., , and X. Xu, 1997: Northern Hemisphere summer monsoon singularities and climatological intraseasonal oscillation. J. Climate, 10 , 10711085.

    • Search Google Scholar
    • Export Citation
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The Dynamics of Phase Locking

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  • 1 Department of Meteorology, The Florida State University, Tallahassee, Florida
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Abstract

Many low-frequency phenomena such as the Madden–Julian oscillation (MJO) or the El Niño–Southern Oscillation (ENSO) exhibit rapid growth where they appear to be undergoing a phase locking with other time scales such as the annual cycle. The purpose of this paper is to illustrate an example of phase locking of two different time scales. In this instance it is shown that during such epochs of phase locking a large increase in nonlinear energy exchange occurs from one time scale to the other. This paper utilizes the ECMWF Re-Analysis (ERA-40) datasets for the year 2001 to examine this problem. This study is a sequel to a recent modeling study where the maintenance of the MJO time scale was examined from scale interactions, especially with synoptic-scale waves with ∼2–7 day periods. It was shown that a pair of waves on the synoptic time scale can satisfy certain selection rules and undergo triad interactions (kinetic energy to kinetic energy exchanges) and transfer energy. This present study illustrates the fact that during epochs of phase locking such nonlinear interactions can become very large, thus portraying the importance of phase locking. These explosive exchanges are shown from two perspectives: an approach based on kinetic energy exchanges in the frequency domain and another that invokes the boundary layer dynamics in the frequency domain.

* Additional affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India

Corresponding author address: Prof. T. N. Krishnamurti, Department of Meteorology, The Florida State University, Tallahassee, FL 32306-4520. Email: tnk@io.met.fsu.edu

Abstract

Many low-frequency phenomena such as the Madden–Julian oscillation (MJO) or the El Niño–Southern Oscillation (ENSO) exhibit rapid growth where they appear to be undergoing a phase locking with other time scales such as the annual cycle. The purpose of this paper is to illustrate an example of phase locking of two different time scales. In this instance it is shown that during such epochs of phase locking a large increase in nonlinear energy exchange occurs from one time scale to the other. This paper utilizes the ECMWF Re-Analysis (ERA-40) datasets for the year 2001 to examine this problem. This study is a sequel to a recent modeling study where the maintenance of the MJO time scale was examined from scale interactions, especially with synoptic-scale waves with ∼2–7 day periods. It was shown that a pair of waves on the synoptic time scale can satisfy certain selection rules and undergo triad interactions (kinetic energy to kinetic energy exchanges) and transfer energy. This present study illustrates the fact that during epochs of phase locking such nonlinear interactions can become very large, thus portraying the importance of phase locking. These explosive exchanges are shown from two perspectives: an approach based on kinetic energy exchanges in the frequency domain and another that invokes the boundary layer dynamics in the frequency domain.

* Additional affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India

Corresponding author address: Prof. T. N. Krishnamurti, Department of Meteorology, The Florida State University, Tallahassee, FL 32306-4520. Email: tnk@io.met.fsu.edu

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