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

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

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)