1National Polytechnic Advanced School of Engineering of Yaounde, University of Yaounde I, Cameroon
Journal of Geosciences and Geomatics.
2025,
Vol. 13 No. 1, 1-22
DOI: 10.12691/jgg-13-1-1
Copyright © 2025 Science and Education PublishingCite this paper: Mfeze Michel. Harmonic Modeling of Tidal Fluctuations in the Wouri Estuary: A Unified Analysis for Accurate Tide Prediction at the Port Authority of Douala.
Journal of Geosciences and Geomatics. 2025; 13(1):1-22. doi: 10.12691/jgg-13-1-1.
Correspondence to: Mfeze Michel, National Polytechnic Advanced School of Engineering of Yaounde, University of Yaounde I, Cameroon. Email:
mfeze@yahoo.frAbstract
Tidal variations between three stations located in the Wouri estuary in Cameroon over a semi-decadal period are examined to more accurately characterize tides in the area. A unified harmonic analysis method using multiple software platforms allows for precise characterization of tidal components as well as more reliable long-term prediction. The iteratively reweighted least squares method with a Cauchy weighting function ensures resistance to outliers and increases the overall accuracy of the modeling. The models explain approximately 100% of the total variance, demonstrating exceptional data reconstruction. The high spectral resolution, obtained through 68 constituents, allows for a detailed representation of the tide. The reliability of the results is reinforced by the use of the Monte Carlo method to estimate confidence intervals, which are colored by a unitary Lambert Scargle oversampling factor. Their narrowness indicates high precision in estimating amplitudes and phases. An automatic adjustment is performed with a unitary minimal threshold without inclusion of trend and without application of pre-filtering correction. Thus, the method effectively adapts to irregularly spaced data, characteristic of tidal observations. Finally, the application of exact nodal and satellite corrections improves the accuracy of long-term predictions, especially since the phase shift for the Greenwich constituent is determined from astronomical arguments. Calculated residuals and statistical tools such as correlations allow for comparative analysis and visualization of data in temporal and spatial domains. The prediction models are finally validated by statistical analysis, and by comparison with real data acquired a posteriori and with other prediction sources such as SHOM. The absence of inference reinforces the credibility of this validation, as the models are based on direct observations rather than extrapolations. The results show better accuracy of our models and also that the tides for the three stations have similar trends and patterns with strong correlation.
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