Propagation and amplification of tide at the northeastern coast of the Antarctic peninsula: an observational study

The amplification and propagation of the tide at the northeastern coast of the Antarctic Peninsula was studied by analysis of instantaneous sea levels measured at the tidal station of Base Esperanza,at the northern end of the Antarctic Peninsula (63゜22.46\u27S, 56゜59.33\u27W) ,at the northeastern coast of Marambio Island (Seymour Island,64゜14.11\u27S, 56゜34.51\u27W) and near Base Matienzo,Larsen nunatak (64゜54.23\u27S, 60゜2.60\u27W) at the edge of the Larsen ice-shelf. By means of harmonic analysis the amplitudes and phases of the most energetic ten tidal constituents were obtained.The tidal regime was typified by means of the factor F and a preponderantly semidiurnal mixed tide was obtained. Signi ficant southward amplification was observed in the amplitudes of semidiurnal constituents,and a less evident amplification was obtained in diurnal ones.Consequently,slightly southward diminution in factor F,from 0.75 (Esperanza) to 0.6 (Matienzo),was found.Bothsouthward amplification in amplitudes and northward propagation of the main tidal constituents obtained from numerical global models show good agreement with the present observations

A numerical study of the ocean circulation around the northern Antarctic Peninsula: Barotropic response to tidal forcing

A high-resolution shallow water model was implemented to study tidal propagation around the northern Antarctic Peninsula. Numerical experiments were done using a grid with 3.00′longitude and 1.05′latitude resolution. Amplitudes and phases of the four main tidal constituents (M_2, S_2, K_1 and O_1) were used to force the model. Modeled sea levels and currents were compared with observations. The modeled cotidal, corange and tidal ellipse axis obtained by harmonic analysis from model results are in good agreement with those of available observations. Given the good correspondence between harmonic constants obtained from model results and from observed hourly sea levels, the energy flux and dissipation by bottom friction were computed. The most intense energy fluxes are related to the semidiurnal constituents. The highest values are present in the Weddell Sea and the energy flux shows a relative maximum at the Antarctic Strait, flowing from the Weddell Sea to Bransfield Strait. Nearly all the dissipation occurs in the Antarctic Strait (maximum value ～0.25Wm^(-2)) and around the South Shetland Islands. The total tidal energy lost to bottom friction in our 4-constituent model is about 1.5GW, giving a domain-averaged value of ～0.002Wm^(-2)

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