Application of the Mohid-2D model to a mesotidal temperate coastal lagoon

1. IntroductionA mathematical model can be considered as anapproximate reconstruction of a real phenomenon.All parameterizations and approximations used inmodels lead to deviations of the model results fromnature. It is an accepted requirement that anumerical model of estuarine hydrodynamicsshould be verified, calibrated and validated beforeused in a practical application. However, theprocedures to perform these tasks are not widelyaccepted (Cheng et al., 1991). Calibration andvalidation methods appear in several forms, de-pending on data availability, water mass character-istics and researchers’ opinion (Hsu et al., 1999).In this work, the Mohid-2D model implementa-tion for the Ria de Aveiro lagoon is presented,describing its assessment through calibration andvalidation against several different data sets. Due tothe lagoon complex geometry and the large numberof calibration stations used, this goal constitutes avery challenging task.The model is calibrated using as a first approach aqualitative comparison of the temporal evolution ofsea surface elevation (SSE) data measured in 1987/1988 at several locations. When a good match isobtained for all stations, the model’s accuracy isevaluated through the determination of the rootmean square (RMS) error and also through thecomparison between amplitude and phase of themain tidal constituents determined from harmonicanalysis of the observed and computed data. Thevalidation procedure is performed using two in-dependent data sets, which includes observations ofcurrent velocities and SSE values (1997 data) andmeasured water fluxes at the lagoon’s inlet for theperiod of October 2002.2. The study areaRia de Aveiro (Fig. 1) is a shallow mesotidallagoon located in the Northwest coast of Portugalð40 38