Estructura mareológica en norpatagonia utilizando el modelo WQMAP

El modelo hidrodinámico bidimensional WQMap, de amplio uso internacional, ha sido aplicado en el área de los tres golfos norpatagónicos (San Matías, San José y Nuevo) y aguas adyacentes de la plataforma continental argentina. Como datos de entrada al modelo indicado, se han utilizado la batimetría más actualizada y, para aplicar como condición de contorno en los bordes abiertos, la marea brindada por los modelos globales más confiables (se optó por el OSU). Después de diseñar una grilla de mucho detalle (con retículo casi cuadrado, de aproximadamente 1700 metros de lado) y de encontrar la estabilidad numérica correspondiente se seleccionaron 402 puntos distribuidos en el recinto, para los que WQMap generó, en cada uno de ellos, las series temporales de un mes de duración de la topografía (marea) y del movimiento (corriente) de las aguas. Luego, dichas series fueron analizadas con el método armónico obteniéndose los valores de las constantes (amplitud y fase) de las principales ondas tanto de la marea como de las componentes de la corriente. En particular, se analizaron dos ondas diurnas (Oj y KJ, tres semidiumas (N2, M2 y S2) más importantes energéticamente y una cuartodiuma (MJ. Se han realizado comparaciones de los resultados obtenidos con aquellos que fueron calculados a partir de datos de mediciones realizadas con anterioridad. Con las constantes armónicas de cada componente en los 402 puntos y mediante el Surfer, un programa muy adecuado para obtener óptimas distribuciones espaciales de isolíneas, se generaron, por un lado, las cartas de cotidales e isoamplitudes de las ondas de marea ya señaladas, y por otro, las correspondientes elipses de comente. Las configuraciones brindadas permiten tener una adecuada imagen de la propagación y de la amplificación de las ondas de marea en esta región del litoral marítimo patagónico.The hydrodynamic two-dimensional model, WQMap, of ample international use, has been applied in the area of the three northpatagonian gulfs (San Matías, San Jose and Nuevo) and adjacent waters of the Argentinian continental platform. About the input data to force the model, the bathymetry more updated has been used. Amplitudes and phases derived from Oregon State University (OSU) global model were used to force the model along the open boundaries. After to design a regular grid (each element almost square of approximately 1700 meters of side) and to find the numerical stability corresponding, 402 points were selected in the domain, for which WQMap generated, in each one of them, the temporary series of a month of duration of the topography (tide) and the movement (current) of waters. Then, these series were analyzed with the harmonic method, obtaining the values of the constants (amplitude and phase) of the mainwaves. In particular, two diurnal waves (Ot andKJ, and three semidiurnal waves (N2, M2 and S2) and one quarter diurnal (MJ were analyzed to characterize the hydrodynamic state. Comparisons between the obtained computational results with the values calculated from data of measurements made previously. With the harmonics constants of each component in the 402 points and by means of the Surfer, a program to obtain optimal space distributions, were generated, on the one hand, the cotidal and corange charts of the tidal waves, and, on the other hand, the corresponding tidal current ellipses. The offered configurations allow having a suitable pattern of the propagation and the amplification of the tidal waves in the northpatagonian maritime coast.Material digitalizado en SEDICI gracias a la colaboración de la Facultad de Ciencias Astronómicas y Geofísicas (UNLP).Asociación Argentina de Geofísicos y Geodesta

Propagation and amplification of tide at the Bransfield and Gerlache Straits, northwestern Antarctic Peninsula

The propagation and amplification of the tide at the Gerlache and Bransfield Straits, northwestern side of the Antarctic Peninsula, was studied by analysis of thirteen series of direct sea level measurements. Harmonic analysis was performed to obtain the amplitudes and phases of the M_2, S_2, O_1 and K_1 tidal constituents. Based on the computed harmonic constants, cotidal and corange charts of these main constituents were prepared. The M_2 cotidal lines are parallel to the coast and show predominantly southeastward propagation, except at the western side of the Trinity Peninsula, where the M_2 wave pivots to enter the Bransfield Strait from the Weddell Sea and turns southwestward. M_2 amplitudes present a southwestward decrease. S_2 cotidal lines are normal to the Antarctic Peninsula coast and show southwestward propagation. S_2 corange lines increase eastward from the Gerlache Strait to the Antarctic Strait. O_1 and K_1 cotidal lines are also normal to the Antarctic Peninsula coast. Diurnal amplitudes are alike in the study area except at the northwestern side of the Antarctic Strait where they present a maximum gradient. Amplitudes of the main tidal constituents are higher in the northwestern Weddell Sea than at the northwestern side of the peninsula. This fact explains the maximum tidal amplitudes observed at the Antarctic Strait in comparison to the Bransfield Strait

One-dimensional tidal model of the Ría San Julián, Argentina

Se implementó un modelo numérico unidimensional para sistemas de canales interconectados con el fin de simular la hidrodinámica de la marea de la ría San Julián, Argentina. En posiciones prefijadas dentro del sistema se pronosticaron la altura de la superficie libre y los caudales, utilizando un método implícito en diferencias finitas. Los resultados de la simulación numérica se compararon con mediciones de campo, y se obtuvo una correlación satisfactoria entre marea y corrientes predichas y observadas.A one-dimensional numerical model for a system of interconnected channels was implemented to simulate the tidal hydraulics of the Ría San Julián, Argentina. Free surface displacement and discharge were computed from predetermined locations throughout the system using an implicit, finite-difference technique. The results of the numerical simulation were compared with field measurements, and a satisfactory correlation was obtained between observed and predicted tides and currents.Este documento es bilingüe: español-inglésFacultad de Ciencias Naturales y Muse

Estudio de la marea en el borde de la barrera Larsen, Mar de Weddell noroccidental

El objetivo de este trabajo es el estudio de la marea en el borde de la barrera Larsen (latitud: 64° 54' 14" S, longitud: 60° 02' 36" W) en el mar de Weddell noroccidental, Antártida. Los niveles del mar se registraron con un sensor de presión y mediante nivelación geométrica (mira y nivel). El coeficiente de determinación de los niveles del mar obtenidos con ambas técnicas es de 0.96. Se presentan las constantes armónicas de las componentes de marea más energéticas. Se realiza un análisis comparativo entre las constantes calculadas y las que surgen de modelos mareológicos globales y se discute la propagación de la marea en el mar de Weddell noroccidental. Se tipificó el régimen de marea cuantitativamente mediante el coeficiente de Courtier resultando un régimen mixto preponderantemente semidiurno. Los niveles del mar registrados en esta zona de la Antártida son inéditos debido a que el sitio de mediciones fue inaccesible durante muchos años.The objective of this paper is the study of the tide at the Larsen iceshelf boundary (latitude: 64° 54' 14" S, longitude: 60° 02' 36" W), Northwestern Weddell Sea, Antarctica. Sea levels were recorded using pressure sensor and geometric leveling (sight and level). The determination coefficient from sea level gathered with both methods is 0.96. Harmonic constants of the most energetic tidal constituents are presented. A comparative analysis between calculated harmonic constants and those obtained from tidal global models is made and tidal propagation in the Northwestern Weddell Sea is discussed. Tidal regimen is quantified by means of the Courtier coefficient and a preponderantly semidiurnal mixed tide is obtained. Sea levels gathered in this zone of the Antarctica are completely new because the place where the measurements were made was inaccessible for a large period of years.Asociación Argentina de Geofísicos y Geodesta

Predicción de Corrientes de Marea Subsuperficiales en Profundidades Bajas e Intermedias

O desenvolvimento de investigacoes sobre dinâmica costeira exige o conhecimento das correntes de mare em diferentes profundidades oceânicas. O modelo aqui proposto permite obter velocidades de correntes de mares atraves de series de medidas proximas a superficie da agua. Este modelo considera o fator de viscosidades relacionado a turbulencia como constante, ao mesmo tempo que introduz o efeito Coriolis. A investigacao e orientada para a componente de energia maxima M 2 e os resultados sao comparados com as series de medidas em diferentes profundidades. Esta comparacao permite concluir pela validade do modelo para predicao da direcao e sentido de rotacao da corrente, bem como fornece uma aceitavel resposta as suas velocidades.Investigation in coastal dynamics, it requires the knowledge of tidal currents at different depths. The model presented here permits to find out their speeds parting from sole series measured near the surface. The model considers the Turbulent viscosity to be constant and introduces the Coriolis effect. The investigation is oriented on The maximal energy component M2 and the computed results are compared with the series measured at different depths. This comparison concludes that the model predicts the direction and the sense of rotation of the current, and that it gives an acceptable answer in the speed modulus.Facultad de Ciencias Naturales y Muse