Global Ocean Tide
The astronomical tide is generated using the harmonic constants derived from the TPXO global tides model, developed by Oregon State University. TPXO is a series of fully-global models of ocean tides, which best-fits, in a least-squares sense, the Laplace Tidal Equations and along track averaged data from altimetry data. The methods used to compute the model are described by Egbert et al. (1994) and further details are provided by Egbert and Erofeeva (2002). The database includes eight primary (M2, S2, N2, K2, K1, O1, P1, Q1), two long period (Mf,Mm), and 3 non-linear (M4, MS4, MN4) harmonic constituents (plus 2N2 and S1 for TPXO9). The database provide the harmonic constituents data over a global grid, the spatial resolution depents of the database version, the TPXO8-atlas provide the data at 1/30 degree resolution in zones near to the coast and 1/6 degree resolution for the rest of the Ocean. This information is used to reconstruct hourly time series of tide in any location worlwide using OSU Tidal Prediction Software.