Three-dimensional slow Rossby waves in rotating spherical density stratified convection [CL]

We develop a theory of three-dimensional slow Rossby waves in rotating spherical density stratified convection. The excited by a non-axisymmetric instability, slow Rossby waves with frequency that is much smaller than the rotating frequency, interact with the density stratified convection and the inertial waves. The density stratification is taken into account using the anelastic approximation for very low-Mach-number flows. This theory is applied for the study of long-term planetary Rossby waves with periods which are larger than two years. The slow Rossby waves are related to the Southern Oscillation and El Ni\~{n}o. The El Ni\~{n}o is an irregularly periodical variation in winds and sea surface temperatures over the tropical Pacific Ocean, while the Southern Oscillation is an oscillation in surface air pressure between the tropical eastern and the western Pacific Ocean. The strength of the Southern Oscillation is measured by the Southern Oscillation Index (SOI). The developed theory of the slow three-dimensional Rossby waves is applied for the interpretation of the observed periods of SOI. This study demonstrates a good agreement between the theoretical predictions and the observations.

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T. Elperin, N. Kleeorin and I. Rogachevskii
Thu, 18 May 17

Comments: 6 pages, 4 figures, REVTEX4-1