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The decay of cyclonic eddies by Rossby wave radiation

McDonald, NR; (1998) The decay of cyclonic eddies by Rossby wave radiation. Journal of Fluid Mechanics , 361 237 - 252. 10.1017/S0022112098008696. Green open access

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Abstract

It is argued that because shallow water cyclones on a β-plane drift westward at a speed equal to an available Rossby wave phase speed, they must radiate energy and cannot, therefore, be steady. The form of the Rossby wave wake accompanying a quasi-steady cyclone is calculated and the energy flux in the radiated waves determined. Further, an explicit expression for the radiation-induced northward drift of the cyclone is obtained. A general method for determining the effects of the radiation on the radius and amplitude of the vortex based on conservation of energy and potential vorticity is given. An example calculation for a cyclone with a ‘top-hat’ profile is presented, demonstrating that the primary effect of the radiation is to decrease the radius of the vortex. The dimensional timescale associated with the decay of oceanic vortices is of the order of several months to a year.

Type: Article
Title: The decay of cyclonic eddies by Rossby wave radiation
Open access status: An open access version is available from UCL Discovery
DOI: 10.1017/S0022112098008696
Publisher version: http://dx.doi.org/10.1017/S0022112098008696
Language: English
Additional information: © 1998 Cambridge University Press
Keywords: applied, Geophysical Fluid Dynamics, Radiation
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Mathematics
URI: https://discovery.ucl.ac.uk/id/eprint/96858
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