Premium
A Rossby whistle: A resonant basin mode observed in the Caribbean Sea
Author(s) -
Hughes Chris W.,
Williams Joanne,
Hibbert Angela,
Boening Carmen,
Oram James
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069573
Subject(s) - rossby wave , baroclinity , geology , mode (computer interface) , boundary current , structural basin , climatology , wavelength , oceanography , sea level , oceanic basin , instability , geophysics , ocean current , physics , geomorphology , optoelectronics , computer science , mechanics , operating system
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.