Please use this identifier to cite or link to this item:
http://dspace.mediu.edu.my:8181/xmlui/handle/10261/5387| Title: | On the relevance of diapycnal mixing for the stability of frontal meanders |
| Keywords: | Diapycnal mixing Barotropic instability Meanders Oceanic jets Atmospheric jets |
| Publisher: | CSIC - Instituto de Ciencias del Mar (ICM) |
| Description: | Publicación online disponible en: http://www.icm.csic.es/scimar/index.php This work examines the possible importance of shear-induced diapycnal mixing in controlling the evolution and stability of meanders in oceanic frontal jets. We first review the conditions necessary for vortex stability and investigate how these may be modified in the presence of diapycnal mixing. The procedure used is rather crude but provides a measure of the relative importance of diapycnal mixing. It consists in constructing a simplified equation for the radial velocity that retains the density tendency and examining under what circumstances this velocity may grow in time. Next, we use a simple two-dimensional isopycnic model to examine the intensity of diapycnal mixing in meanders. In the model the along-front velocity is in geostrophic balance and the ageostrophic contributions are an oscillating deformation field and diapycnal mass exchange. The horizontal deformation field increases the slope of the isopycnals in temporal scales typical of Gulf Stream meanders, causing a reduction of the gradient Richardson number, Ri. The diapycnal flux is calculated as the divergence of the density Reynolds flux, which is parameterized in terms of Ri. The results of the model show that diapycnal mixing increases during the frontogenetical stages, reaching density tendency values of the order of 10-4 kg m-3s-1 and convergence/divergence values of the order of 10-3 s-1. It turns out that diapycnal mixing in meanders may be intense enough to control the separation and slope of the isopycnals and to condition the possibility of barotropic instability. This work was supported by the Spanish government trhough projects FRENTES (CICYT grant AMB95-0731) and TALUD (CICYT MAR96-1893) and the European Union through project CANIGO (MAST-CT96-0060). Peer reviewed |
| URI: | http://dspace.mediu.edu.my:8181/xmlui/handle/10261/5387 |
| Other Identifiers: | Scientia Marina 65(Suppl.1): 259-267 (2001) 0214-8358 (print edition) 1886-8134 (online edition) http://hdl.handle.net/10261/5387 10.3989/scimar.2001.65s1259 |
| Appears in Collections: | Digital Csic |
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.