Geophysical Research Letters

From AGU Publications

A Rossby Whistle: A resonant basin mode observed in the Caribbean Sea†
Authors
Chris W. Hughes,
Joanne Williams,
Angela Hibbert,
Carmen Boening,
James Oram

Abstract

We show that an important source of coastal sea level variability around the Caribbean Sea is a resonant basin mode. The mode consists of a baroclinic Rossby wave which propagates westward across the basin and is rapidly returned to the east along the southern boundary as coastal shelf-waves. Almost two wavelengths of the Rossby wave fit across the basin, and it has a period of 120 days. The porous boundary of the Caribbean Sea results in this mode exciting a mass exchange with the wider ocean, leading to a dominant mode of bottom pressure variability which is almost uniform over the Grenada, Venezuela and Colombia basins, and has a sharp spectral peak at 120 day period. As the Rossby waves have been shown to be excited by instability of the Caribbean Current, this resonant mode is dynamically equivalent to the operation of a whistle.

DOI

10.1002/2016GL069573
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Format Available

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© 2016. American Geophysical Union. All Rights Reserved.

Keywords

Caribbean Sea; Sea Level; Bottom Pressure; Rossby Wave; Basin Mode
Publication History

Accepted manuscript online: 19 June 2016
Manuscript Revised: 13 June 2016
Manuscript Accepted: 13 June 2016
Manuscript Received: 12 May 2016
Index terms:

Eddies and mesoscale processes
Planetary waves
Sea level: variations and mean

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IMAGE: The Caribbean Sea en.wikipedia.org