Wind-driven coastal circulation in the Gulf of Tehuantepec, Mexico

Abstract

Sea surface current measurements and wind stress and sea surface temperature satellite data were used to study the effect of northerly wind events (Tehuanos) on coastal dynamics in the Gulf of Tehuantepec, Mexico. The winter 2005 observations show a significant change in the intensity and direction of surface currents during wind events, which is reflected in an increase in kinetic energy and negative relative vorticity. The analysis revealed that kinetic energy of the coastal current decreases (increases) in periods when there is absence (presence) of Tehuano wind events, and that the relative vorticity has a tendency to positive values under low wind conditions and a tendency to negative values during high wind events. An asymmetric ocean response was observed due to wind stress forcing and the interaction between a persistent coastal current and offshore wind stress.

Influence of post‐Tehuano oceanographic processes in the dynamics of the CO2 system in the Gulf of Tehuantepec, Mexico

“…Another mesoscale structure of importance in relation to carbon chemistry in the GoT is the coastal current that flows to the northwest. Although this has been reported previously as a surface current by other authors [ Barton et al ., ; Flores‐Vidal et al ., ; Machain‐Castillo et al ., ; Velázquez‐Muñoz et al ., ], in the present study, it occurred as a surface current to the east and a subsurface one to the west. This current functions as a DIC advection mechanism.…”

“…Temporal coverage of data used in this study is not enough to discern whether this flow is a constant current or derives from eddy rims associated mainly with cyclonic eddies (Figure ). Previous studies refer to a poleward coastal current detected at the same region during winter, spring, and summer [ Barton et al ., ; Flores‐Vidal et al ., ; Trasviña and Barton , ; Willett et al ., ; Velázquez‐Muñoz et al ., ]. Furthermore, geostrophic velocity in section I (Figure ) indicates a poleward subsurface flow in spite of the coastal upwelling and the anticyclonic eddy.…”

“…The most frequent structure is an anticyclonic eddy at the GoT western region [ Barton et al ., ; Willett et al ., ], which can last several months. Also reported is the presence of a cyclonic eddy in the eastern/central GoT, as well as a coastal current to the east that travels north/northwest parallel to the coast [ Barton et al ., ; Velázquez‐Muñoz et al ., ]. Once the Tehuano season is over, during May–June [ Romero‐Centeno et al ., ], the GoT becomes highly stratified, displaying a strong pycnocline [ Fiedler et al ., ], mesoscale structures, and coastal‐trapped waves related to baroclinic instabilities [ Flores‐Vidal et al ., ].…”

Alpha diversity of marine mammals of the Mexican South Pacific

“…Mesoscale eddies are generated in winter (dry season) (Trasviña & Barton, 2008) directly associated with the Tehuan events, jet winds locally called "Tehuanos, Tehuantepecanos or Nortes" (Trasviña et al, 2003;Reyes-Hernández et al, 2016), although it has also been observed that eddies non-associated to the wind can be produced (Flores-Vidal et al, 2011). The currents and sea surface temperature show temporal variability near the coast of the GT when these events occur in the winter (Velázquez-Muñoz et al, 2011), particularly upwelling in the GT and a notable decrease in sea surface temperature (Trasviña et al, 2003). In this area there is a coastal current of approximately 100 km wide, that flows from westwards, which can be persistent throughout the year causing the entry of a warm water mass to the GT (Velázquez-Muñoz et al, 2011).…”

“…The currents and sea surface temperature show temporal variability near the coast of the GT when these events occur in the winter (Velázquez-Muñoz et al, 2011), particularly upwelling in the GT and a notable decrease in sea surface temperature (Trasviña et al, 2003). In this area there is a coastal current of approximately 100 km wide, that flows from westwards, which can be persistent throughout the year causing the entry of a warm water mass to the GT (Velázquez-Muñoz et al, 2011). It has also been shown that the flow of this surface current is interrupted by Tehuano winds of moderate to strong intensity (Reyes-Hernández et al, 2016).…”