Ocean tides in the colombian basin and atmospheric contribution to S2

The tidal behavior in the Colombia basin is described based on the analysis of eighteen tide gauge time series, fourteen in the Colombian coasts and four placed in neighboring countries. Tidal constituents are published for the first time at nine of these stations. Harmonic analysis shows that the main constituents in the Caribbean correspond to three diurnals (K₁, O₁, P₁); three semidiurnals (M₂, N₂, S₂), and one long period harmonic (M_f), showing amplitudes and phase lag that correspond to previous tidal reports in the basin. In Turbo, due to the shallow and extensive continental shelf in the Urabá gulf, M₂ is amplified, and shallow water harmonics appear. The amplitude and phase of each observed constituent are compared with global tide models FES2014, TPXO9 and DTU10, showing good agreement. The most significant differences occur with semidiurnal harmonics at stations close to the amphidromic point in the eastern Caribbean. In M_f, considerable interannual variations are found, supporting the need of over one year of sea level data to assess this constituent in the Colombia basin accurately. The radiational component of S₂ is assessed using barometric pressure in thirteen stations, confirming its importance when compared to the gravitational contribution to the observed sea level harmonic. A trend in the atmospheric S₂ is found in Cartagena, which supports those trends in sea-level S_2, previously reported in the Caribbean Sea, are caused by variations in the radiational forcing.