A study of 2-D coastal hyrodynamic model calibration with Mike 21

Recently, numerical models have become very popular tools applicable to many problems inhydraulic and environmental engineering. They are replacing physical scale models whichwere commonly applied in the past.The most important concern in front of being put into practice of any developed numericalmodeling is the process of model parameter adjustments, also known as ?calibration?. Thecalibration of the model for an hydrodynamic model would be achieved if there is a goodmatch that make discrepancy between observed and simulated values of the followinghydrodynamic parameters minimum : (1) surface elevation, (2) current speed and (3) currentdirection. However, in order to support the match involved, error functions concerning withstatistical measurements such as ?root mean square error (RMSE)? must be considered.The traditional method of model calibration is the process in which parameter adjustments isapplied manually by using a trial and error procedure. The process of manual calibration,however, may be a very tedious and time consuming task, depending on the number of freemodel parameters and the degree of parameter interaction.In recent years, many research studies have been carried out to develop automated calibrationmethods that would replace this time-consuming process. The automatic calibration schemesgenerally involve optimization of an objective function that compares discrepancy betweenobserved and simulated values. So, calibration problem is treated as an optimization problemand solution algorithms are developed in this direction.In this present study, the hydrodynamic model calibration and parameter optimizationtechniques are reviewed. MIKE 21 HD modeling software is used throughout the study tocarry out test runs. The study focuses on different steps of model calibration includingdetermination of input parameters, selection of calibration parameters, evaluation of objectivefunctions and the choice of optimization algorithms. A case study is also presented to providea practical application of the presented theoretical work.Key Words: Hydrodynamic calibration, automatic calibration, optimization, Mike 21 Hd,numerical model