eprintid: 96855
rev_number: 58
eprint_status: archive
userid: 608
dir: disk0/00/09/68/55
datestamp: 2010-10-19 12:01:07
lastmod: 2021-10-04 01:30:54
status_changed: 2012-10-22 15:38:54
type: article
metadata_visibility: show
item_issues_count: 0
creators_name: Wake, GW
creators_name: Ivey, GN
creators_name: Imberger, J
creators_name: McDonald, NR
creators_name: Stocker, R
title: Baroclinic geostrophic adjustment in a rotating circular basin
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F59
keywords: NONLINEAR ROSSBY ADJUSTMENT, KELVIN WAVES, ENERGETICS, CHANNEL, LAKE, GRAVITY
note: © 2004 Cambridge University Press
abstract: Baroclinic geostrophic adjustment in a rotating circular basin is investigated in a laboratory study. The adjustment process consists of a linear phase before advective and dissipative effects dominate the response for longer time. This work describes in detail the hydrodynamics and energetics of the linear phase of the adjustment process of a two-layer fluid from an initial step height discontinuity in the density interface DeltaH to a final response consisting of both geostrophic and fluctuating components. For a forcing lengthscale r(f) equal to the basin radius R-0, the geostrophic component takes the form of a basin-scale double gyre while the fluctuating component is composed of baroclinic Kelvin and Poincare waves. The Burger number S=R/r(f) (R is the baroclinic Rossby radius of deformation) and the dimensionless forcing amplitude epsilon = DeltaH/H-1 (H-1 is the upper-layer depth) characterize the response of the adjustment process. In particular, comparisons between analytical solutions and laboratory measurements indicate that for time tau: 1 < tau < S-1 (tau is time scaled by the inertial period 2pi/f), the basin-scale double gyre is established, followed by a period where the double gyre is sustained, given by S-1 < tau < 2epsilon(-1) for a moderate forcing and S-1 < tau < tau(D) for a weak forcing (tau(D) is the dimensionless dissipation timescale due to Ekman damping). The analytical solution is used to calculate the energetics of the baroclinic geostrophic adjustment. The results are found to compare well with previous studies with partitioning of energy between the geostrophic and fluctuating components exhibiting a strong dependence on S. Finally, the outcomes of this study are considered in terms of their application to lakes influenced by the rotation of the Earth.
date: 2004-09-25
publisher: CAMBRIDGE UNIV PRESS
official_url: http://dx.doi.org/10.1017/S0022112004000230
vfaculties: VMPS
oa_status: green
language: eng
primo: open
primo_central: open_green
article_type_text: Article
verified: verified_manual
elements_source: Web of Science
elements_id: 49415
doi: 10.1017/S0022112004000230
language_elements: EN
lyricists_name: McDonald, Nicholas
lyricists_id: NRMCD79
full_text_status: public
publication: J FLUID MECH
volume: 515
pagerange: 63 - 86
issn: 0022-1120
citation:        Wake, GW;    Ivey, GN;    Imberger, J;    McDonald, NR;    Stocker, R;      (2004)    Baroclinic geostrophic adjustment in a rotating circular basin.                   J FLUID MECH , 515    63 - 86.    10.1017/S0022112004000230 <https://doi.org/10.1017/S0022112004000230>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/96855/1/download4.pdf