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Interpreting the upper level structure of the Madden-Julian oscillation

Monteiro, Joy M and Adames, Angel F and Wallace, John M and Sukhatme, Jai S (2015) Interpreting the upper level structure of the Madden-Julian oscillation. In: GEOPHYSICAL RESEARCH LETTERS, 41 (24). pp. 9158-9165.

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Official URL: http://dx.doi.org/ 10.1002/2014GL062518


The nonlinear response of a spherical shallow water model to an imposed heat source in the presence of realistic zonal mean zonal winds is investigated numerically. The solutions exhibit elongated, meridionally tilted ridges and troughs indicative of a poleward dispersion of wave activity. As the speed of the jets is increased, the equatorial Kelvin wave is unaffected but the global Rossby wave train coalesces to form a compact, amplified quadrupole structure that bears a striking resemblance to the observed upper level structure of the Madden-Julian oscillation. In the presence of strong subtropical westerly jets, the advection of planetary vorticity by the meridional flow and relative vorticity by the zonally averaged background flow conspire to create the distinctive quadrupole configuration of flanking Rossby waves.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA
Department/Centre: Division of Mechanical Sciences > Divecha Centre for Climate Change
Date Deposited: 23 Mar 2015 10:09
Last Modified: 23 Mar 2015 10:09
URI: http://eprints.iisc.ac.in/id/eprint/51098

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