DENSITY FRONTS IN THE VICINITY OF A LONG RIDGE

Citation
F. Hreinsson et al., DENSITY FRONTS IN THE VICINITY OF A LONG RIDGE, Dynamics of atmospheres and oceans, 27(1-4), 1998, pp. 283-300
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oceanografhy,"Metereology & Atmospheric Sciences","Geochemitry & Geophysics
Journal title
ISSN journal
0377-0265
Volume
27
Issue
1-4
Year of publication
1998
Pages
283 - 300
Database
ISI
SICI code
0377-0265(1998)27:1-4<283:DFITVO>2.0.ZU;2-2
Abstract
Laboratory experiments concerning the nature of density fronts in a tw o-layer fluid in the vicinity of a continuous ridge were conducted. Th e experiments were carried out in a circular rotating test cell contai ning an annular ridge of uniform cross-section. The density fronts wer e established by releasing a lighter fluid contained in a bottomless c ylinder in the interior of the region defined by the topography into a heavier fluid occupying the rest of the test cell. The system was als o equipped with an oscillating plunger located along the test cell axi s to produce simulated tidal currents impinging in the normal directio n on the ridge; experiments without and with tidal forcing were conduc ted. The governing parameters for the physical system considered are t he Rossby, temporal Rossby, Burger and Ekman numbers and geometrical p arameters. It is found that for both the non-forced and tidally forced experiments the fronts were stabilized by the ridge. The fronts in th e simulated tidal currents experiments were found to advect radially o utward more rapidly at early times than their non-forced counterparts; at large times, the temporal evolution of the front for these forced experiments approached that of the non-forced experiments. In the regi on interior to the annular ridge, the motion field is highly baroclini c, while outside this region, the flow response at the forcing frequen cy is barotropic. Scaling arguments regarding frontal position, viscou s decay and barotropic oscillatory flow responses are advanced and sup ported by experimental observations. (C) 1997 Elsevier Science B.V.