Divergent pathways of cyclonic and anti‐cyclonic ocean eddies

Abstract

[1] Satellite altimetry is used to study the propagation pathways of warm and cold ocean eddies in different ocean basins. We consider eddies that have a life span longer than 3 months, and we present three regional studies: in the southeast Indian, the southeast Atlantic, and the northeast Pacific Oceans. The case studies show that simple theories for vortex propagation on a b-plane work in regions where energetic eddies propagate though a weak background flow. Under these conditions, anticyclonic/cyclonic eddies propagate westward and equatorward/poleward. This divergence in the eddy pathways implies a net equatorward eddy heat flux, and has implications for the meridional transport of freshwater, carbon, nutrients, etc.

Identification of jets and mixing barriers from sea level and vorticity measurements using simple statistics

“…The pattern of the first rotated EOF for sea level is clearly very similar to the skewness map presented by Thompson and Demirov (2006). Major eastward currents are delineated by the boundary 5 6 between large positive and large negative values, and preferred paths of eddies, such as in the Alaskan Stream along the Aleutian island chain at the northern boundary of the Pacific (Ueno et al, 2009), and southwest of Australia (Morrow et al, 2004) also stand out. The tropical Pacific is also prominent.…”

Pathways of mesoscale variability in the South China Sea

“…In the eastern and central SCS, mesoscale signals mainly show the westward propagation velocities, which are widely observed in the world oceans and attributed to the influence of baroclinic Rossby waves (Morrow et al, 2004;Chelton et al, 2007). Thus the eddy energy generated west of the Luzon Island will transfer westward, resulting in weak local MV.…”

Agulhas leakage into the Atlantic estimated with subsurface floats and surface drifters

“…Morrow et al (2004) Mediterranean water eddies (meddies) that translate equatorward with some nearby cyclones translating poleward (Richardson et al, 2000). In the western Indian Ocean, de Ruijter et al (2005) found that anticyclones and cyclones form off the southern tip of Madagascar and tend to disperse westward as observed in the Cape Basin.…”

“…They appear to enter the Agulhas and translate downstream possibly triggering the shedding of Agulhas rings and cyclones. The different meridional translation direction of the eddies is primarily due to the β effect (Cushman-Roisin, 1994; Morrow et al, 2004). Eddies can also be advected by the background flow field as in the case of Agulhas rings, and eddies can interact with and be advected by other nearby eddies.…”

“…Some of the cyclones observed with floats and altimetry seem to have originated near the eastern boundary, and most of them translated southwestward Morrow et al, 2004).…”