On coastal currents off Tehuantepec

Alvarez, Luis G.; Badan‐Dangon, Antoine; Valle, Antonio B. do

doi:10.1016/0272-7714(89)90075-9

Cited by 14 publications

(9 citation statements)

References 11 publications

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“…As the CRCC weakens in winter, Barton et al (2009) also found northerly wind-driven anticyclonic circulation on the western side of the Gulf of Tehuantepec, as well as eastward and westward coastal currents at the west and east sides of the wind axis, respectively, in a similar fashion to that described by Roden (1961) and Alvarez et al (1989). It is remarkable that the observed buoyancy-driven coastal westward current was a persistent feature during the two surveys, exhibiting temperature, salinity and geostrophic characteristics consistent with the concept of the CRCC, just as Brenes et al (2008) identified it.…”

Section: Introductionsupporting

confidence: 57%

The Costa Rica Coastal Current, eddies and wind forcing in the Gulf of Tehuantepec, Southern Mexican Pacific

Reyes-Hernández

Ahumada-Sempoal

Durazo³

2016

Continental Shelf Research

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Section: Introductionsupporting

confidence: 57%

The Costa Rica Coastal Current, eddies and wind forcing in the Gulf of Tehuantepec, Southern Mexican Pacific

Reyes-Hernández

Ahumada-Sempoal

Durazo³

2016

Continental Shelf Research

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“…The three major mountain gaps are located at the Isthmus of Tehuantepec, the lowlands of central Nicaragua, and Panama, and the strong offshore winds in the lee of these mountain gaps are known as the Tehuantepec, Papagayo, and Panama jets, respectively. The influence of these wind jets on local processes over the adjacent Pacific waters, such as the generation of large warm oceanic eddies, intense offshore currents, increase in turbulent heat fluxes, considerable drop of the SST by upwelling and entrainment of subsurface water, and increase in biological activity, has motivated many studies, which have especially focused on the Gulf of Tehuantepec (e.g., Roden 1961;Stumpf 1975;Stumpf and Legeckis 1977;Alvarez et al 1989;McCreary et al 1989;Lavín et al 1992; Barton et al 1993;Trasviña et al 1995;Lluch-Cota et al 1997;Schultz et al 1997;Steenburgh et al 1998;Bourassa et al 1999;Muller-Karger and Fuentes-Yaco 2000;Zamudio et al 2006).…”

Section: And References Within)mentioning

confidence: 99%

Midsummer Gap Winds and Low-Level Circulation over the Eastern Tropical Pacific

2007

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The low-level seasonal and intraseasonal wind variability over the northeastern tropical Pacific (NETP), its relationship with other variables, and the connection with large- and middle-scale atmospheric patterns are analyzed using a suite of datasets. Quick Scatterometer (QuikSCAT) wind data show that the low-level circulation over the NETP is mainly affected by the northerly trades, the southerly trades, and the wind jets crossing through the Tehuantepec, Papagayo, and Panama mountain gaps. The seasonal and intraseasonal evolution of these wind systems determines the circulation patterns over the NETP, showing predominant easterly winds in winter and early spring and wind direction reversals in summer over the central region of the NETP. During summer, when southerly trades are the strongest and reach their maximum northward penetration, weak westerlies are observed in June, easterlies in July–August, despite that strong southerlies tend to turn eastward, and again westerlies in September–October. This circulation pattern appears to be related to the Tehuantepec and Papagayo jets, which slightly strengthen during midsummer favored by the westward elongation and intensification of the Azores–Bermuda high (ABH). This ABH evolution induces an across-gap pressure gradient over the Isthmus of Tehuantepec favoring the generation of the jet and a meridional sea level pressure (SLP) gradient in the western Caribbean that favors the funneling of the trade winds through the Papagayo gap. The SLP pattern causing the gap winds in winter is different than in midsummer, being the southeastward intrusion of high pressure systems coming from the northwest, the main cause of the large meridional SLP gradients in Tehuantepec and the western Caribbean. The westward low-level circulation observed over the central-eastern region of the NETP during midsummer induces westward moisture fluxes in the lower layers of the atmosphere, displaces convergence areas away from the coasts, and confines the relatively strong convergence in the easternmost NETP to the south of the area of influence of the wind jets and associated easterlies, contributing to the development of the midsummer drought observed in southern Mexico and Central America.

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“…Moreover, modeling studies have highlighted the possible contribution of instability of coastally trapped Kelvin waves to the formation of the anticyclones even in the absence of wind (Zamudio et al, 2006). However, apart from the early large-scale studies of Wyrtki (1965) and Blackburn (1962), and the localized drifter studies of Alvarez et al (1989), the only in situ measurements reported of the hydrography and currents in the area remain those of the experiment described by Lavín et al (1992), Barton et al (1993) and Trasviña et al (1995;. Like the other studies, those reports concentrated on the spin-up of the anticyclonic eddies and on the dramatic response of the central GoT to wind forcing, but neglected the near-shore circulation, which has a more direct effect on local fisheries and coastal ecology.…”

Section: Introductionmentioning

confidence: 99%

Coastal circulation and hydrography in the Gulf of Tehuantepec, Mexico, during winter

Barton

Lavín

Trasviña

2009

Continental Shelf Research

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Winter observations of shelf and slope hydrography and currents in the inner Gulf of Tehuantepec are analysed from two field studies in 1989 and 1996 to specify the variability of near-shore conditions under varying wind stress. During the winter period frequent outbursts of ´Norte´ winds over the central Gulf result in persistent alongshore inflows along both its eastern and western coasts. Wind-induced variability on time scales of several days strongly influences the shelf currents, but has greater effect on its western coast because of the generation and separation of anticyclonic eddies there. The steadier inflow (~0.2 m s-1) on the eastern shelf is evident in a strong down-bowing of shallow isosurfaces towards the coast within 100 km of shore, below a wedge of warmer, fresher and lighter water. This persistent entry of less saline (33.4-34.0), warmer water from the southeast clearly originates in buoyancy input by rivers along the Central American coast, but is augmented by a general shoreward tendency (0.2 m s-1) in the southeastern Gulf. The resultant shallow tongue of anomalous water is generally swept offshore in the head of the Gulf and mixed away by the strong outflow and vertical overturning of the frequent 'Norte' events but during wind relaxations the warm, low salinity coastal flow may briefly extend further west. In the head of the Gulf, flow is predominantly offshore (<0.2 m s-1) as the alongshore component alternates eastward and westward in association with elevation or depression, respectively, of the pycnocline against the shore. More saline, open ocean water is introduced from the northwestern side of the Gulf by the inflow along the west coast. During extended wind relaxations, the flow becomes predominantly eastward beyond the shelf while near shore the coastally trapped buoyant inflow from the southeast penetrates across the entire head of the gulf at least as far as its western limit. On the basis of these and other recent observations, it seems that the accepted view of a broad, persistent Costa Rica Coastal Current is the result of averaging over many relatively sparse observations and that the instantaneous CRCC is a highly variable and convoluted flow around and between constantly changing eddies. The buoyancy-driven shelf current reported here forms a hitherto unrecognized, but major, component of this CRCC system.

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On coastal currents off Tehuantepec

Cited by 14 publications

References 11 publications

The Costa Rica Coastal Current, eddies and wind forcing in the Gulf of Tehuantepec, Southern Mexican Pacific

The Costa Rica Coastal Current, eddies and wind forcing in the Gulf of Tehuantepec, Southern Mexican Pacific

Midsummer Gap Winds and Low-Level Circulation over the Eastern Tropical Pacific

Coastal circulation and hydrography in the Gulf of Tehuantepec, Mexico, during winter

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