The Surface Circulation of the Caribbean Sea and the Gulf of Mexico as Inferred from Satellite Altimetry

Abstract

The surface circulation of the Caribbean Sea and Gulf of Mexico is studied using 13 years of satellite altimetry data. Variability in the Caribbean Sea is evident over several time scales. At the annual scale, sea surface height (SSH) varies mainly by a seasonal steric effect. Interannually, a longer cycle affects the SSH slope across the current and hence the intensity of the Caribbean Current. This cycle is found to be related to changes in the wind intensity, the wind stress curl, and El Niñ o-Southern Oscillation. At shorter time scales, eddies and meanders are observed in the Caribbean Current, and their propagation speed is explained by baroclinic instabilities under the combined effect of vertical shear and the b effect. Then the Loop Current (LC) is considered, focusing on the anticyclonic eddies shed by it and the intrusion of the LC into the Gulf of Mexico through time. Twelve of the 21 anticyclonic eddies observed to detach from the LC are shed from July to September, suggesting a seasonality in the timing of these events. Also, a relation is found between the intrusion of the LC into the Gulf of Mexico and the size of the eddies shed from it: larger intrusions trigger smaller eddies. A series of extreme LC intrusions into the Gulf of Mexico, when the LC is observed as far as 928W, are described. The analyses herein suggest that the frequency of such events has increased in recent years, with only one event occurring in 1993 versus three from 2002 to 2006. Transport through the Straits of Florida appears to decrease during these extreme intrusions.Corresponding author address: Aida Alvera-Azcá rate, AGO-GHER, University of Liè ge, Allé e du 6 Aoû t 17,

The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico

“…The mesoscale circulation in the GoM is dominated by the presence of the LC and the LC eddies. The LC enters the GoM basin through the Yucatan Channel and leaves through the Straits of Florida (Weisberg et al, 2000;Alvera-Azcárate et al, 2009). It influences the south part of the domain directly and is usually confined to the east of 86°W (Vukovich, 2007).…”

Sea level extremes in the Caribbean Sea

“…The Caribbean Sea is an eddy-rich region [Chelton et al, 2007] where eddies can generate sea level anomalies in the order of few decimeters [Alvera-Azcarate et al, 2009;Andrade and Barton, 2000], while the tidal contribution is small [Torres and Tsimplis, 2011]. Mesoscale eddies have been reported to be a main contributor to sea level extremes events at places where sea level variations are small [Firing and Merrifield, 2004].…”

A Lagrangian approach to the Loop Current eddy separation

“…Although the mechanisms and frequency of LCE shedding have been studied by many authors, critical aspects of the process remain uncertain (Alvera-Azcarate et al, 2009;Maul and Vukovich, 1993;Sturges, 1994;Vukovich, 1995). Some authors have discussed several events where small cyclonic eddies on the periphery of the Loop Current influence the shedding of the LC rings (Fratantoni et al, 1998;Zavala-Hidalgo et al, 2003;Chérubin et al, 2006;Schmitz, 2005).…”

“…Some authors have discussed several events where small cyclonic eddies on the periphery of the Loop Current influence the shedding of the LC rings (Fratantoni et al, 1998;Zavala-Hidalgo et al, 2003;Chérubin et al, 2006;Schmitz, 2005). Using 3 yr of direct mooring observations together with altimetry data Athié et al (2011) find that some shedding events are associated with cyclonic anomalies coming from the Caribbean producing an eastward shift of the LC core. Downstream from the LC, Sturges et al (2010) finds perturbations in the transport measurements from the cable between Miami and the Bahamas that precede several LCE detachments.…”