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Relationship between eddy‐driven jet latitude and width
Author(s) -
Kidston J.,
Vallis G. K.
Publication year - 2010
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 - 10.1029/2010gl044849
Subject(s) - barotropic fluid , vorticity , jet (fluid) , instability , enstrophy , physics , potential vorticity , latitude , mechanics , jet stream , middle latitudes , baroclinity , atmospheric sciences , geology , vortex , astronomy
The relationship between the latitude and the width of the eddy‐driven jet is examined. We find that there is strong correlation between jet latitude and jet width, with jets located towards the pole being broader. The broadening of the jet with increased latitude appears to be a consequence of increased barotropic instability. When the jet is located towards the pole, the reduced planetary vorticity gradient is more easily overwhelmed by the negative relative vorticity gradient on the flanks of the jet, and this allows a horizontal shear instability to occur. Enstrophy diagnostics show that when the condition of a negative vorticity gradient is met, the effects of barotropic instability are indeed more prevalent.