Numerical Characterization of Harbor Oscillations in the Port of Ensenada, Mexico

Abstract

A series of numerical experiments from a barotropic configuration of the General Curvilinear Ocean Model (GCOM) was conducted to analyze the response to infragravity (IG) waves of the Port of Ensenada, located within Bahia de Todos Santos (BTS), west coast of Mexico. Experiments with forcing frequencies f = 50?1 min?1, f = 30?1 min?1, f = 25?1 min?1 and f = 16.66?1 min?1 showed the expected increase of energy at the corresponding forcing frequency band and also the appearance of secondary peaks of energy at frequency bands f = 8.33?1 min?1 and f = 4.16?1 min?1 which were identified as modes f 1 and f 2 ; being the band at f = 16.66?1 min?1 the zeroth f 0 mode. Maximum peak of spectral energy from the numerical experiments was found at frequency band f 0 = 16.66?1 min?1 which agreed with the estimated maximum value of the amplification factor and with the T 0 mode of oscillation of the port. Distribution of amplitudes inside PE for modes f 0 , f 1 and f 2 were also presented. Mode f 0 represents a quarter-wave oscillation with amplitudes of the same sign; mode f 1 has two nodal lines and mode f 2 presents and additional one. Corresponding harbor currents were also calculated, they were in the range 20 - 160 cm?s?1. Finally, in order to elucidate the source of the external signals found in the spectral analysis of this study, the natural oscillation modes of the BTS were estimated. Although more studies are needed, BTS oscillation mode T 2 = 16.82 min, was identified as the external forcing that excites larger oscillations within the port.