Baroclinic Eddy Interactions with Continental Slopes and Shelves

Topographic effects on the anticyclonic vortex evolution: A modeling study

“…The poleward drift is generated as the vortex rotates clockwise (Fig. 13c) and is likely caused by the "image effect", the tendency of the zonally compressed vortex drifting along the wall as if there were an opposite sign of vortex on the other side (Shi and Nof, 1993;Sutyrin et al, 2003). Similar poleward motion for anticyclones was also reported in the LCE by Kirwan et al (1988) and in North Brazil current rings (Fratantoni et al, 1995).…”

“…Jacob et al (2002) questioned whether vortex baroclinicity/barotropicity affected vortex-topography interactions and what the influences of topographic orientation were, and suggested that vortex propagation over a slope strongly depended on the barotropicity of the vortex, the orientation and steepness of the slope, and that a northward-sloping topography increased the propagation speed because both the planetary and topographic /( effects were in the same direction, whereas a southward-sloping slope decreased the speed. Sutyrin et al (2003) investigated the Loop Current Eddy (LCE) translation over an idealized northwestern GoM slope using a two-layer model, and reported that a deep cyclone near the trailing edge of an upper vortex accelerated southward translation, and that a northward translation along the western boundary was induced by the 'image' effect. Frolov et al (2004) investigated the effects of two typical configurations of slope geometry in the western GoM (wide shelf-narrow slope/narrow shelf-wide slope) on the LCE-topography interaction, and showed that a southward translation occurred on both slopes with an oscillated cyclic trajectory but the cyclic motion was critically controlled by the slope width.…”

“…Recall that most observed ocean vortices have a dominant zonal drift with a very slow meridional drift (e.g. Morrow et al, 2004), and that the ocean is not flat even though numerous model experiments exhibited a substantially strong meridional translation over a flat bottom (Sutyrin et al, 2003; Herbette et al, 2005). Chassignet and Cushman-Roisin (1991) suggested that reduced gravity approximation, which assumed an infinitely deep lower layer at rest, was only valid for vortices smaller than the deformation radius.…”

“…of the vortex in layer 13. Sutyrin et al (2003) suggested that southward vortex translation was strongly accelerated by the deep cyclone, and decreased as the deep cyclone dispersed over the slope. For the weak slope case (Wl), the vortex is weaker (more dissipative) than BO and the deep cyclone tilts slightly upslope in layer 14 and its center shoals to ~300m (Fig.…”

“…and 13% of the initial vortex cross the shelf break in W3, W4, W5, respectively, after 2 years of translation. An experiment without the continental shelf (not included) was performed in order to see whether the vortex translates northward along the western boundary by the 'image effect' (Sutyrin et al, 2003). That case exhibited continuous southward translation along the boundary with enhanced dissipation.…”