Frequency of Ring Separations from the Loop Current in the Gulf of Mexico: A Revised Estimate

Analysis of flow variability in the Yucatan Channel

“…For example, Maul [1977] suggests an intrusion is associated with the dephasing of the maximum transport in Yucatan and Florida Straits, and Leipper [1970] found that the Loop Current had a maximum northward intrusion into the Gulf during the summer months, but a lesser intrusion during the winter. This result, however, has been found unwarranted by more recent observations [e.g., Sturges and Leben, 2000] which show no clear seasonal signal in Loop Current intrusions. Numerical and theoretical modeling studies suggest the eddy-shedding process may be associated to instabilities of the Yucatan Current [Hurlburt and Thompson, 1980], the lack of momentum conservation of steady-state solutions [Pichevin and Nof, 1997], and the flux of potential vorticity anomalies through the Yucatan Channel [Candela et al, 2003].…”

“…The Yucatan and Loop Currents, together with the Florida Current, are part of the western boundary circulation of the North Atlantic Subtropical Gyre, which results from the flow compensating the Sverdrup transport in the interior of the Atlantic, and from the surface limb of the large-scale meridional overturning cell (MOC) [Schmitz and Richardson, 1991]. The Yucatan Current passes through the Yucatan Channel and becomes the Loop Current, a predominant feature of the circulation in the Gulf, but the variations in the Loop Current and the shedding of eddies from it remain poorly understood; most studies report eddy-shedding periods from 3 to 17 months [Elliott, 1982;Maul and Vukovich, 1993;Sturges and Leben, 2000]. The intrusions of the Loop Current into the Gulf have been attributed to different characteristics of the Yucatan Current.…”

Fish Resources of the Gulf of Mexico

“…There is large spatiotemporal variability in oceanographic conditions, with the Gulf of Mexico influenced greatly by inflows and discharges from rivers and other land-based sources, including the Mississippi River, and by large-scale oceanographic features, such as the Loop Current and associated core eddies of different thermal conditions (Govoni and Grimes 1992; Sturges and Leben 2000). Combined, these factors result in large spatiotemporal variability in physicochemical conditions, causing primary production to vary markedly within and across areas of different oceanographic conditions in the Gulf of Mexico (Grimes and Finucane 1991;Biggs 1992).…”

“…It contains a rich variety of larval tropical fishes that grow and settle on the reefs of the eastern Gulf of Mexico, while eddies transport additional species into the western Gulf of Mexico (McEachran and Fechhelm 2005). The Loop Current may further act as an important geographic isolating mechanism that separates inshore fish populations of the eastern and western Gulf of Mexico (Govoni and Grimes 1992;Sturges and Leben 2000). This may result in the degree of endemism found in the western Gulf of Mexico (Shipp 1992).…”

An integrated ocean circulation, wave, atmosphere, and marine ecosystem prediction system for the South Atlantic Bight and Gulf of Mexico

“…The Loop Current originates at the Yucatan Channel, through which approximately 23∼27 Sv (1 Sv = 10 6 m 3 /s) transport passes (Johns et al 2002;Sheinbaum et al 2002). The Loop episodically sheds warm-core rings (Vukovich et al 1979) at intervals of approximately 3-18 months (Sturges & Leben 2000). Tides are generally weak in the Gulf, but strong tropical and extratropical storms often pass through the region, acting as strong synoptic forcing agents for water transport, mixing, and entrainment in the regional ocean (Shay & Uhlhorn 2008).…”