Premium
Effects of Topography and Orientation on the Nonlinear Equilibration of Baroclinic Instability
Author(s) -
Brown Justin M.,
Gulliver Larry T.,
Radko Timour
Publication year - 2019
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2019jc015297
Subject(s) - baroclinity , instability , potential vorticity , zonal and meridional , vorticity , nonlinear system , zonal flow (plasma) , geostrophic wind , mechanics , flow (mathematics) , geology , physics , climatology , vortex , quantum mechanics , plasma , tokamak
This study attempts to identify the equilibration mechanisms of baroclinic instability and investigate the effects of the orientation of the background flow and topography on eddy‐induced transport. The analysis is based on growth rate balance theory, which assumes that nonlinear equilibration occurs when the growth rate of the primary baroclinic instability becomes comparable to that of the secondary instabilities of amplifying modes. Two‐layer quasi‐geostrophic numerical simulations are performed and compared to growth rate balance theory in order to analytically predict the cross‐stream fluxes of potential vorticity. The model performs remarkably well in predicting the effects of variation in zonal topographic slope and background flow orientation. We find that meridional topographic slopes affect the baroclinic instability in an inherently nonlinear way. A predictive model based on conservation of potential vorticity is developed for the optimal slope that maximizes the transport characteristics of the baroclinic instability.