Remolinos en el Golfo de Ancud: Un análisis numérico.
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Date
2025
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Universidad de Concepción
Abstract
Esta investigación analiza el origen y la dinámica de remolinos de mesoescala en el Golfo de Ancud (41,8°–42,2°S, 73,5°–73,9°O), ubicado en el Mar Interior de Chiloé (MIC), Chile. Se realizaron simulaciones numéricas de alta resolución con el modelo CROCO, complementadas con experimentos de sensibilidad y descomposición armónica de mareas, para evaluar la influencia de distintos forzamientos—incluyendo mareas astronómicas, batimetría local y vientos climatológicos—en la formación y evolución de los remolinos. Los experimentos de sensibilidad incluyeron: (i) eliminación de la componente mareal, (ii) un escenario con batimetría plana a 150 m de profundidad, y (iii) simulaciones forzadas únicamente por vientos climatológicos. Cada experimento cubrió un mes completo en enero y julio, representando las condiciones de verano e invierno.
Los resultados muestran que los remolinos de mesoescala son estructuras persistentes y dominantes en el Golfo de Ancud, con diámetros típicos de 15–30 km, duraciones de varias semanas y marcada variabilidad estacional. En verano, los remolinos presentan mayor intensidad y concentración, alcanzando velocidades superficiales máximas de hasta 20 cm/s, mientras que en invierno se distribuyen de manera más dispersa y con menor intensidad, aunque mantienen coherencia en profundidad. Los experimentos sin mareas confirman que las mareas astronómicas no son determinantes en la generación de los remolinos, aunque sí pueden modular su intensidad y estabilidad. La batimetría y la circulación regional son los principales factores que controlan su ubicación y estructura.
Estos hallazgos indican que los remolinos de mesoescala son elementos intrínsecos de la circulación local en el Golfo de Ancud, y no estructuras transitorias ni exclusivamente mareales. Este estudio aporta nuevos conocimientos sobre la complejidad dinámica del Mar Interior de Chiloé, resaltando la importancia de considerar el transporte y mezclas inducidos por remolinos en estudios ecológicos, biogeoquímicos y de dispersión de contaminantes. Trabajos futuros podrían incluir análisis de vorticidad y balances de energía, evaluación de variabilidad estacional e interanual, e integración con modelos acoplados océano-atmósfera, permitiendo un entendimiento más profundo de los mecanismos de formación de remolinos, su retroalimentación sobre la circulación regional y sus implicancias para la gestión sostenible del ecosistema marino del sur de Chile.
This study investigates the origin and dynamics of mesoscale eddies in the Gulf of Ancud (41.8°–42.2°S, 73.5°–73.9°W), located within the Chiloé Inland Sea (CIS), southern Chile. High-resolution numerical simulations were conducted using the CROCO model, comple mented by sensitivity experiments and tidal harmonic decomposition, to assess the influen ce of different forcings—including astronomical tides, local bathymetry, and climatological winds—on eddy formation and evolution. The sensitivity experiments included: (i) removal of astronomical tides, (ii) a flattened bathymetry scenario (150 m depth), and (iii) simula tions forced only by climatological winds. Each experiment covered a full month in January and July to represent summer and winter conditions. The results demonstrate that mesoscale eddies are persistent and dominant features of the Gulf of Ancud, with typical diameters of 15–30 km, lifetimes of several weeks, and clear seasonal variability. In summer, eddies were stronger and more concentrated, with maximum surface velocities reaching up to 20 cm/s, while in winter they appeared more dispersed and weaker but remained coherent at depth. Experiments removing tidal forcing confirmed that astronomical tides do not play a primary role in eddy generation, although they may modu late intensity and stability. Bathymetry and regional circulation patterns were found to be the main factors controlling the location and structure of these eddies. These findings indicate that mesoscale eddies are intrinsic elements of the local circulation in the Gulf of Ancud, rather than transient or purely tide-driven features. The study provides new insights into the complexity of the Chiloé Inland Sea dynamics, highlighting the need to consider eddy-induced transport and mixing in ecological, biogeochemical, and pollutant dis persion studies. Future work could include vorticity and energy budget analyses, seasonal and interannual variability assessments, and the integration of coupled ocean-atmosphere models. These approaches would allow for a deeper understanding of eddy formation mechanisms, their feedback on regional circulation, and their implications for sustainable management of the marine ecosystem in southern Chile.
This study investigates the origin and dynamics of mesoscale eddies in the Gulf of Ancud (41.8°–42.2°S, 73.5°–73.9°W), located within the Chiloé Inland Sea (CIS), southern Chile. High-resolution numerical simulations were conducted using the CROCO model, comple mented by sensitivity experiments and tidal harmonic decomposition, to assess the influen ce of different forcings—including astronomical tides, local bathymetry, and climatological winds—on eddy formation and evolution. The sensitivity experiments included: (i) removal of astronomical tides, (ii) a flattened bathymetry scenario (150 m depth), and (iii) simula tions forced only by climatological winds. Each experiment covered a full month in January and July to represent summer and winter conditions. The results demonstrate that mesoscale eddies are persistent and dominant features of the Gulf of Ancud, with typical diameters of 15–30 km, lifetimes of several weeks, and clear seasonal variability. In summer, eddies were stronger and more concentrated, with maximum surface velocities reaching up to 20 cm/s, while in winter they appeared more dispersed and weaker but remained coherent at depth. Experiments removing tidal forcing confirmed that astronomical tides do not play a primary role in eddy generation, although they may modu late intensity and stability. Bathymetry and regional circulation patterns were found to be the main factors controlling the location and structure of these eddies. These findings indicate that mesoscale eddies are intrinsic elements of the local circulation in the Gulf of Ancud, rather than transient or purely tide-driven features. The study provides new insights into the complexity of the Chiloé Inland Sea dynamics, highlighting the need to consider eddy-induced transport and mixing in ecological, biogeochemical, and pollutant dis persion studies. Future work could include vorticity and energy budget analyses, seasonal and interannual variability assessments, and the integration of coupled ocean-atmosphere models. These approaches would allow for a deeper understanding of eddy formation mechanisms, their feedback on regional circulation, and their implications for sustainable management of the marine ecosystem in southern Chile.
Description
Tesis presentada para optar al grado de Magíster en Geofísica.
Keywords
Corrientes marítimas, Torbellinos (Mecánica de fluidos), Dinámica de fluidos