Predicting Tidal Currents Using 25-h Observations through a Complete Tidal Species Modulation with Tidal Current Constant Corrections Method

Abstract

AbstractA new approach enabling the prediction of tidal currents, for observation sites with as little as ≥25 h of data, has been developed as a practical way of utilizing very short tidal current records. We name this technique the complete tidal species modulation with tidal current constant corrections (CTSM+TCCC) method. In addition to a short-term tidal current record from the “observation site,” this technique also requires (i) ideally half a year (specifically, ≥183 days from any time) and (ii) concurrent (≥25 h) sea level observation records from a nearby “reference site.” The reliability of the CTSM+TCCC method is tested for three different tidal current regimes (almost rectilinear, elliptical, and near circular) in Geyonggi Bay, South Korea, using daily slices (25 h long) of 29-day tidal current records from each observation station, plus sea level records from the nearby Incheon reference station. RMSE analysis of the resulting prediction time series demonstrates that the CTSM+TCCC method produces reasonably accurate predictions based on observation station records derived from spring, but not neap, tide periods. We conclude that our method can be successfully employed to make tidal current predictions using 25-h observation station records obtained from spring tide periods, ideally gathered during periods of relatively calm weather. As well as testing the sensitivity of CTSM+TCCC predictions to observation record timing, the effect of reference station location was investigated using records from 20 stations spread along the South Korean coasts. Results revealed that tidal records from nearby tidal current observation and sea level reference stations produce reasonable current predictions, since proximal locations share similar tidal species’ modulated tidal and tidal current behaviors.