INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS Int. J. Numer. Meth. Fluids 2009; 60:651–667 Published online 10 September 2008 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/fld.1910 Applying local model approach for tidal prediction in a deterministic model Yabin Sun 1 , Piyamarn Sisomphon 2, ∗, † , Vladan Babovic 1, 2 and Eng Soon Chan 1, 3 1 Department of Civil Engineering, National University of Singapore, Singapore 2 Singapore-Delft Water Alliance, National University of Singapore, Singapore 3 Tropical Marine Science Institute, National University of Singapore, Singapore SUMMARY In recent years, a practice of tidal prediction based on a deterministic model or by a time series forecasting model has been established. A deterministic model can predict tidal movement and capture the dynamics of the flow pattern over the entire domain. However, due to the simplification of model settings and near shore effects, the accuracy of the numerical model can diminish. Time series forecasting is capable of capturing the underlying mechanism that may not be revealed in the deterministic model simulation. However, such data-driven forecast fails to maintain accuracy with the progress of forecast horizon. In this paper, a scheme that combines the advantages of these two methods is introduced. The model errors are forecasted to different time horizons using a data-driven approach, and are then superimposed on the simulation results in order to correct the model output. Based on the proposed method, it is found that the accuracy is significantly improved with more than 50% of the errors removed on the average. Copyright 2008 John Wiley & Sons, Ltd. Received 20 February 2008; Revised 24 May 2008; Accepted 29 July 2008 KEY WORDS: local model; chaos theory; genetic algorithm; tidal prediction; error correction; determin- istic model 1. INTRODUCTION Tidal prediction is of prime importance for ship navigation and scheduling of harbor operations. Prediction could be made for time horizons from several hours to several days, which is helpful in the finalization of operational schedules and many other coastal activities. The current practice of tidal prediction is undertaken by either using a tidal predictive deterministic model or by a time series forecasting model. Each of the above two approaches has its own capabilities and deficiencies ∗ Correspondence to: Piyamarn Sisomphon, Strategic Research and Development, Deltares, The Netherlands. † E-mail: ann.sisomphon@deltares.nl Contract/grant sponsor: Singapore-Delft Water Alliance (SDWA); contract/grant number: R-264-001-001-272 Copyright 2008 John Wiley & Sons, Ltd.