The coastal upwelled waters of the Guajira coast, the most northerly peninsula of South America, were studied on the basis of historical and remotely sensed data, and three oceanographic cruises. The Guajira Peninsula is the locus of particularly strong upwelling because it protrudes into the Caribbean Low Level Wind Jet and its west coast parallels the direction of the strongest winds. The year-round upwelling varies with the wind forcing: strongest in December-March and July, and weakest in the October-November rainy season. The east-west temperature, salinity and density front that delimits the upwelling lies over the shelf edge in the east of the peninsula but separates from the south-westward trending topography to the west. A coastal westward surface jet geostrophically adjusted to the upwelling flows along the front, and an eastward sub-surface counterflow is trapped against the Guajira continental slope. The undercurrent shoals toward the western limit of the upwelling, Santa Marta, beyond which point it extends to the surface. Some of the westward jet re-circulates inshore with the counterflow but part continues directly west to form an upwelling filament. Much of the mesoscale variation is associated with upwelling filaments, which expel cooler, chlorophyll-rich coastal upwelling waters westward and northward into the Caribbean Sea. Freshwater plumes from the Magdalena and Orinoco rivers influence the area strongly, and outflow from Lake Maracaibo interacts directly with upwelled waters off Guajira. Another important factor is the Aeolian input of dust from the Guajira desert by episodes of offshore winds.

Abstract. Eddy motion in the Caribbean

[1] Hydrographic transects suggest an eastward flow with a subsurface core along the entire southern boundary of the Caribbean Sea. The transport of the coastal limb of the Panama-Colombia Gyre (PCG), known as the Panama-Colombia Countercurrent, decreases toward the east (from $6 Sv off Panama), as water is lost into the recirculation of the PCG. Off Panama, the flow is strongest at the surface, but, off Colombia, it is strongest at around 100 m. A portion of the counterflow ($1 Sv) continues eastward along the Colombian coast as far as the Guajira region (12°N, 72°W), where it submerges to become an undercurrent beneath the coastal upwelling center there. The eastward flow also occurs in the Venezuela Basin, beneath the coastal upwelling region off Cariaco Basin and exits the Caribbean through the Grenada Channel at around 200 m depth. Numerical simulations suggest that this flow, counter to the Caribbean Current, is a semi-continuous feature along the entire southern boundary of the Caribbean, and that it is associated with offshore cyclonic eddies. It probably constitutes part of the Sverdrup circulation of the Tropical North Atlantic cyclonic cell.

No abstract

Se describen los patrones de dispersión de la pluma turbia del canal del Dique en la bahía de Cartagena mediante el análisis de 69 imágenes SPOT y los resultados de una simulación numérica para determinar los principales mecanismos de formación de los patrones de la pluma turbia en la bahía. Se detectaron seis patrones principales de la dispersión de la pluma, mediante la selección de casos homólogos. El modelo hidrodinámico aplicado permitió imitar la pluma turbia e identificar las condiciones hidro-meteorológicas para cada uno de los patrones.Palabras claves: Bahía de Cartagena, imágenes SPOT, modelos numéricos, turbidez, canal del Dique.The dispersion patterns of the turbid plume of Canal del Dique in Cartagena Bay are described through the analysis of 69 SPOT images and the results of the numerical modeling designed to detect the principal mechanisms for the formation of the turbid plume patterns from the Dique channel at the Cartagena Bay. Six different patterns of the plume were detected based on homologous selection. The implemented hydrodynamic model simulated the turbid plume and identified the hydrometeorological conditions for each pattern.