Abstract:
Conventional tidal computation techniques used many number of
parameters like tidal constituents, datum, residuals in the modeling process.
Because of this reason, they are inappropriate in real time onboard
applications. Here, the observed tidal fields are assumed to be obeying the
two-dimensional (2D) Laplace’s Equation (LE) and the interpolation is
computed by numerically solving the LE. The appropriate boundary
conditions were tested using simulated test blocks and real data at Malacca
Straits. Ceaseless Co-Tidal Chart (CCTC) and Direct Tidal Observation
Spatial Interpolation Technique (DTOSIT) are two new approaches
developed for fast modeling and computation of offshore tide. These two
methods are significance from other existing techniques as it is not using the
individual tidal constituents for the interpolation. Then, Matlab computer
application was developed to provide fast, accurate and continuous tidal
corrections for onboard bathymetric reduction based on the observed tides at
the Malacca Straits. Results were compared against the shore stations and in
offshore with the satellite altimetry sea surface heights. Furthermore, tidal
datum variability over the region was also modeled. The statistical results
showed a very good correlation over 0.9 with the observed and the modeled
tidal values. DTOSIT tidal modeling has given slightly higher correlation
than the predicted CCTC tides as it used the observed tide in the modeling.
The standard deviations of the computed datum levels were around 0.1m
and satisfied the International Hydrographic Organization’s standards for
the datum. It is clear that this approach is a fast and effective approach in
modeling the tidal phenomenon.
