Functions in S_TIDE
FOR DOCUMENTATION
s_readme.m - this function briefly introduces all functions in S_TIDE
FOR DEMONSTRATION
s_demo.m - demonstration codes for all functions in S_TIDE
FOR AUXILIARY ANALYSIS
s_plot_tidal_ellipse.m - plot tidal ellipse
s_plot_tidal_ellipse2.m - plot tidal ellipse at full depth
s_estimate_tidal_ellipse.m - calculate the parameters of tidal ellipse
s_construct.m - construct water levels by given tidal information without nodal factor/angle
s_nodal_cal.m - calculate the nodal factor and angle for given tides
s_construct2.m - construct water levels by given tidal information and nodal factor/angle (at middle time)
s_construct22.m - a revised version of s_construct2.m, which can simultaneously construct water levels at numerous locations.
s_construct3.m - construct water levels by given tidal information and nodal factor/angle (at each time)
s_tidalcharacter.m - calculate the basic tidal characters (such as skewness, high and low tides) from given water levels
s_alias.m - calculate the alias period caused by long-period satellite sampling
s_minimumLOR.m - calculate the minimum length of records to resolve given constituents
s_eot.m - function to read EOT20 tide models
s_equilibrium_tide.m - calculate equilibrium tidal levels
s_estimate_max_tidalcurrent.m - calculate the maximum possible tidal current speed with given N constituents
s_tdd.m - calculate the theoretical depth datum with given N constituents
s_rotation_spectra.m - calculate the rotation spectrum of currents
s_rtl.m - calculate the riding high/low tide levels from given water levels
s_rtl2.m - a modified version of s_rtl.m
s_modaldecomposition.m - dynamical modal decomposition for internal tides
s_modaldecomposition2.m - dynamical modal decomposition for internal tides,with regularization methods
s_earthtide.m - function to calculate theoretical earth tides/ocean tides potential
s_draw_tidalchart.m - function to draw co-tidal charts using EOT20 ocean tidal model
s_inertial.m - function to calculate the latitude which can generate near inertial oscillations whose frequencies are same as given tidal constituents
s_rS2.m - function to calculate radiational S2 tides from observed M2, S2, N2，K2 tides
s_wavelength.m - function to calculate the wave velocity and length of tidal constituents at given water depth
s_vector.m - function to realize vector operation (plus or minus)
s_tidetable.m - function to generate tide table with given hourly water level observations
s_HAreport.m - function to generate tidal analysis report (in the form of doc)
FOR TIDAL HARMONIC ANALYSIS
s_RHA.m - a revised harmonic analysis model which can consider non-astronomical external forcing (e.g. ENSO, Pan et al., 2025, doi: 10.1016/j.pocean.2024.103410)
s_MHACS - a modified harmonic analysis model designed for short-term tidal observations based on the credo of smoothness (Pan et al., 2023, doi: 10.1016/j.ocemod.2023.102251)
s_MHACS2 - an improved version of s_MHACS which can realize ridge regression and Lasso regression (Pan et al., 2024, doi: 10.1016/j.ocemod.2024.102372)
s_MHACSe - error estimation for MHACS
s_highlowtides - function to perform harmonic analysis for high and low tides (Pan et al., 2024, doi: 10.1016/j.csr.2024.105179)
s_quasi_HA.m - quasi harmonic analysis (for observations more than 24 hours but less than 13 days) using reference relationships from EOT20 model.
s_quasi_HA2.m - a revised version of s_quasi_HA for uneven observations
s_tide.m - computes the tidal analysis of the real tidal time series using Enhanced Harmonic Analysis (EHA) without nodal corrections. Users need to use s_nodal_correction function to nodally correct the amplitudes and phases.
s_tide_m1.m - a modified version of s_tide.m
s_tide_m2.m - a modified version of s_tide.m
s_tide_m3.m - a modified version of s_tide.m (for satellite data)
s_tide_m4.m - a modified version of s_tide.m (for satellite data)
s_tide_m5.m - a modified version of s_tide_m2.m (for uneven data)
s_tide_m55.m - a modified version of s_tide_m5.m (adding weights)
s_tide_m6.m - a modified version of s_tide_m4.m (for uneven satellite data)
s_tide_m66.m - a modified version of s_tide_m6.m (adding weights)
s_tide_m7.m - a modified version of s_tide.m which is designed specifically for estimating linear trends of tidal amplitudes and phases
s_tide_m8.m - a modified version of s_tide_m3.m (only uses nodal factor and angle at central time for nodal correction)
Notes: s_tide series functions use independent point (IP) scheme to obtain temporal variability of tidal parameters. For classical harmonic analysis, IP number should be set as 1, namely, tidal parameters are time-invariant. If IP number is set to 2, linear variations of tidal parameters can be obtained. The increase of IP number can induce more complicated variability in tidal parameters, but also increases the risk of over-fitting. For even tide gauge data, users can use s_tide_m8 function. For even/uneven satellite data, users can use s_tide_m4/s_tide_m6 function. For tidal current data, users need to analyze u and v respectively, and put tidal constants of u and v into s_estimate_tidal_ellipse function to calculate tidal ellipse parameters.