Examinando por Materia "Tides"
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Ítem Análisis de sensibilidad a un modelo de transporte de sedimentos: Golfo de Urabá, Colombia(Universidad EAFIT, 2011) Velásquez Montoya, Liliana; Escobar Sierra, Carlos AlejandroÍtem Estimation of sediment grain sizes in a mesotidal area, Dithmarschen Bight, German North Sea(ELSEVIER SCIENCE BV, 2019-01-01) Escobar, Carlos Alejandro; Mayerle R.; Restrepo D.; Mecánica AplicadaThis article presents a fast and suitable method to derive the spatial distribution of seabed grain sizes on tidal flats. A successful validation was carried out in the Dithmarschen Bight, a meso-tidal area of the German North Sea coast. In particular, the study is built on statistical correlations between observations of sediment sizes from 197 seabed samples and the numerical model output of flow-wave variables under specific marine and atmospheric forcings. The correlation between orbital velocities and mean grain sizes (d50) exhibited the best results, but it can be affected under low relative wave height ratios. The methodology was applied for the construction of a high-resolution map of grain sizes in the Dithmarschen Bight, which resulted in absolute and relative errors of 16 µm and 13%, respectively. The proposed relationship was also adopted to examine scenarios of field data scarcity. © 2019Ítem Introducción a los cambios del nivel del mar y sus consecuencias sobre la zona costera(Centro Editorial de la Facultad de Minas, Universidad Nacionald de Colombia, 2012) Vernette, Georges; Correa Arango, Iván Darío; Bernal Franco, Gladys Rocío; Universidad EAFIT. Escuela de Ingeniería. Grupo de Investigación Ciencias del Mar; Ivan D. Correa-Arango (icorrea@eafit.edu.co)Ítem Modelo hidrodinámico y de oleaje del mar caribe : DELFT Caribe(Universidad EAFIT, 2019) Posada Jaramillo, Federico; Correa Arango, Iván DaríoA two-dimensional large scale mathematical model is presented, which was later migrated to three dimensions, coupling hydrodynamics and waves in the southern Caribbean Sea, named Delft Caribe. The low spatial and temporal coverage of the oceanographic measurements in the study area and the need to know the waves, currents and tides, and the interaction between them at different points of interest led to the construction of this model. The Delft 3D modeling platform was used, which is extensively validated for multidimensional simulation of flows and transport phenomena. The model considers at its borders tidal forcing, atmospheric factors, discharges of tributaries and waves from the Atlantic Ocean. The model results were validated, statistically and qualitatively, for the dry and wet seasons. The good results of the model allow to carry out different experiments aimed to know the performance of the tool to calculate the following: • Velocities of surface currents. • Changes in directions and heights of waves. • Levels of waves. • Changes in the above mentioned variables due to the passage of cold fronts and hurricanes. It was observed that the waves in the southern Caribbean come parallel to the trade winds (Northeast to Southwest) from the Lesser Antilles, to the Guajira peninsula continuing toward the Central American coast of Honduras and Nicaragua, and simultaneously turning south to the Gulf of Urabá and the coasts of Costa Rica and Panama. The significant heights in the model area increased in the dry season and with the passage of storms, with wave heights of: • 6 m in the zone near Guajira Peninsula- • 3 m in the Urabá Gulf. • 3 m in the San Andrés Archipelago zone. The model simulates, in a coherent manner, the Caribbean Current and Panamá Colombia Gyre. The first comes from the Atlantic entering through the model east border and flows to the Guajira Peninsula, where it turns into the Gulf of Mexico and the second is a gyre flowing from Panama to Colombia, with higher velocities during the wet season when the Caribbean current is less strong.Ítem Morphodynamics of a high discharge tropical delta, San Juan River, Pacific coast of Colombia(ELSEVIER SCIENCE BV, 2002-12-30) Restrepo, JD; Kjerfve, B; Correa, ID; Gonzalez, J; Universidad EAFIT. Departamento de Geología; Ciencias del MarThe San Juan River has one of the most extensive and best developed deltas on the Pacific coast of South America, measuring 800 km2. The river drainage basin measures 16465 km2 and is located in one of the areas with the highest precipitation in the western hemisphere. The annual rainfall varies from 7000 to 11 000 mm, and as a result the San Juan River has the highest water discharge (2550 m3 s-1), sediment load (16×106 t yr-1), and basin-wide sediment yield (1150 t km-2 yr-1) on the west coast of South America. The San Juan delta growth began approximately 5000 years BP. The structure of the delta is determined by the interactions between fluvial deposition and the effect of 1.7-m significant swells, mostly from the SW, and strong tidal currents. Analysis of delta progradation indicates that during 1848-1992 the morphology of the delta was characterized by beach ridge accretion, spit growth, narrowing of inlets, and a general advance of the delta shoreline. During the past decade processes such as rapid erosion of the delta shore, narrowing of barrier islands, and breaching of a new inlet, are the result of a long-term relative sea-level rise of 2.6 mm yr-1 due to tectonically induced subsidence coupled with a eustatic rise of sea-level. The delta also experiences strong oceanographic manifestations associated with the El Niño-La Niña cycle, causing regional sea-level elevation of 20-30 cm during El Niño years. Recent coastal subsidence in the delta is evidenced by (1) increased occurrence of non-storm washover events; (2) increased erosion of barrier islands with average loss of 11 m yr-1 during 1993-1997; and (3) a relative sea-level rise of 3.4 mm yr-1 during 1991-1999. The morphology and recent evolution of the San Juan delta are unique when compared to other deltas of South America because of the singular combination of extreme climatic, geologic, and oceanographic conditions under which the delta has formed and the absence of human-induced impact in the drainage basin. © 2002 Elsevier Science B.V. All rights reserved.