Each ADCP cell was considered as an independent time series and each measurement period separately analysed.
ADCP data and current-meter series were treated in the same way, using the same procedure in data analysis.
Quality control was carried out, removing spikes and bad data, while the missing data within the gaps lasting
for less than 6 hours were linearly interpolated. Harmonic analysis (Foreman, 1978) was applied and tidal
constituents with signal-to-noise ratio > 1 were subtracted. Harmonic analysis calculations were done using the
MatLab programme t_tide (Pawlowicz et al., 2002). Finally, a low-pass filter with cut-off period at 33 hours
(Flagg et al., 1976) was applied in order to remove inertial oscillations, thus obtaining sub-inertial non-tidal flow.
Foreman, M.G.G.: Manual for Tidal Currents Analysis and Prediction, Pacific Marine Science Report 78-6,
Institute of Ocean Sciences, Patricia Bay, Sidney, B.C., 57 pp. (2004 revision), 1978.
Pawlowicz, R., Beardsley, B. and Lentz, S.: Classical tidal harmonic analysis including error estimates in
MATLAB using T_TIDE, Computers and Geosciences, 28, 929-937, 2002.