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Rossby wave packet interactions

Published online by Cambridge University Press:  28 March 2006

A. C. Newell
Affiliation:
Department of Planetary and Space Science, Department of Mathematics, University of California, Los Angeles

Abstract

A mechanism is proposed whereby planetary zonal flows can be generated by the resonant interaction of Rossby wave packets whose amplitudes are slowly varying functions of both space and time. Equations are derived describing the long-time behaviour of a resonantly interacting triad. At the first closure certain properties analogous to those already known for discrete waves are deduced. At the second closure, in the particular case when one of the members of the triad is a zonal flow, it is shown that the sideband resonance mechanism can cause energy to be gained or lost by this zonal flow. It is also shown that a single Rossby wave packet can exchange energy with a zonal flow with weak shear. In the final section a resonant quarter mechanism for producing zonal flows is discussed. A numerical estimate of the acceleration of a zonal current from a zero initial state gives values of a few km/day per day.

Type
Research Article
Copyright
© 1969 Cambridge University Press

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References

Benjamin, T. B. & Feir, J. E. 1967 The disintegration of wave trains on deep water J. Fluid Mech. 27, 417.Google Scholar
Benney, D. J. 1962 Non-linear gravity wave interactions J. Fluid Mech. 14, 577.Google Scholar
Benney, D. J. & Newell, A. C. 1967 The propagation of non-linear envelopes J. Math. & Phys. 46, 133.Google Scholar
Benney, D. J. & Newell, A. C. 1969 Random wave closures. Studies in Appl. Math. To appear.
Benney, D. J. & Saffman, P. G. 1966 Non-linear interaction of random waves in a dispersive medium. Proc. Roy. Soc. A 289, 301.Google Scholar
Bretherton, F. P. 1964 Resonant interactions between waves. The case of discrete oscillations J. Fluid Mech. 20, 457.Google Scholar
Charney, J. 1959. On the General Circulation of the Atmosphere. The atmosphere and motion. (The Rossby Memorial Volume.) New York: Rockefeller Inst. Press.
Davis, R. E. & Acrivos, A. 1967 The stability of oscillatory internal waves J. Fluid Mech. 30, 723.Google Scholar
Eliason, E. 1958 A study of long atmospheric waves on the basis of zonal harmonic analysis Tellus, 10, 206.Google Scholar
Hasselmann, K. 1962 On the non-linear energy transfer in a gravity wave spectrum J. Fluid Mech. 12, 481.Google Scholar
Kenyon, K. 1964 Non-linear Rossby waves. Woods Hole Oceanographic Institutio. Summer Study Program in Geophysical Fluid Dynamics, Student Lectures vol. II, 69.
Kenyon, K. 1966 A discussion on nonlinear theory of wave propagation in dispersive systems. Proc. Roy. Soc. A 299, 141.Google Scholar
Longuet-Higgins, M. S. 1964 Planetary waves on a rotating sphere. Proc. Roy. Soc. A279, 446.Google Scholar
Longuet-Higgins, M. S. 1965 Planetary waves on a rotating sphere. II. Proc. Roy. Soc. A 284, 40.Google Scholar
Longuet-Higgins, M. S. & Gill, A. E. 1967 Resonant interaction between planetary waves. Proc. Roy. Soc. A 299, 120.Google Scholar
Miles, J. 1964 Baroclinic instability of the zonal wind Rev. Geophys. 2, 155.Google Scholar
Phillips, O. M. 1960 On the dynamics of unsteady gravity waves of finite amplitude, Part 1. The elementary interactions J. Fluid Mech. 9, 193.Google Scholar
Phillips, O. M. 1967 Studies of gravity wave interactions. Proc. Roy. Soc. A 299, 104.Google Scholar
Whitham, G. B. 1967 Variational methods and applications to water waves. Proc. Roy. Soc. A 299, 6.Google Scholar