A mechanism for jet drift over topography
File(s)Jet_Drft.pdf (5.16 MB)
Accepted version
Author(s)
Khatri, Hemant
Berloff, Pavel
Type
Journal Article
Abstract
The dynamics of multiple alternating oceanic jets has been studied in the presence of a simple bottom topography with constant slope in the zonal direction. A baroclinic quasi-geostrophic model forced with a horizontally uniform and vertically sheared background flow generates mesoscale eddies and jets that are tilted from the zonal direction and drift with constant speed. The governing dynamical equations are rewritten in a tilted frame of reference moving with the jets, and the cross-jet time-mean profiles of the linear and nonlinear stress terms are analysed. Here, the linear stress terms are present because of the zonally asymmetric topography. It is demonstrated that the linear dynamics controls the drift mechanism. Also, it is found that the drifting jets are directly forced by the imposed vertical shear, whereas the eddies oppose the jets, although this is limited to continuously forced dissipative systems. This role of the eddies is opposite to the one in the classical baroclinic model of stationary, zonally symmetric multiple jets. This is expected to be more generic in the ocean, which is zonally asymmetric nearly everywhere.
Date Issued
2018-06-25
Date Acceptance
2018-04-01
Citation
Journal of Fluid Mechanics, 2018, 845, pp.392-416
ISSN
0022-1120
Publisher
Cambridge University Press (CUP)
Start Page
392
End Page
416
Journal / Book Title
Journal of Fluid Mechanics
Volume
845
Copyright Statement
© 2018 Cambridge University Press. This paper has been accepted for publication and will appear in a revised form, subsequent to peer-review and/or editorial input by Cambridge University Press.
Sponsor
Natural Environment Research Council (NERC)
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000431015100002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
NE/R011567/1
Subjects
Science & Technology
Technology
Physical Sciences
Mechanics
Physics, Fluids & Plasmas
Physics
baroclinic flows
quasi-geostrophic flows
topographic effects
MULTIPLE ZONAL JETS
ANTARCTIC CIRCUMPOLAR CURRENT
SHALLOW-WATER TURBULENCE
BETA-PLANE TURBULENCE
SOUTHERN-OCEAN
BAROCLINIC INSTABILITY
GEOSTROPHIC TURBULENCE
JUPITERS ATMOSPHERE
SPECTRAL-ANALYSIS
BAROTROPIC MODEL
Publication Status
Published
Date Publish Online
2018-04-26