Modeling of waves and currents in the nearshore parametric vs. probabilistic approach

• Published in: Coastal engineering (Amsterdam) 2003-09, Vol.49 (3), p.185-207
• Main Authors: Grasmeijer, B.T., Ruessink, B.G.
• Format: Article
• Language: English
• Subjects: Cross-shore currents; Cross-shore profile model; Earth, ocean, space; Exact sciences and technology; External geophysics; Longshore currents; Physics of the oceans; Surface waves, tides and sea level. Seiches; Wave model; Wave-by-wave approach
• ISSN: 0378-3839; 1872-7379
• DOI: 10.1016/S0378-3839(03)00045-0

This paper introduces a hydrodynamic model that can predict the cross-shore transformation of wave height, on- and offshore orbital motion, and time-averaged cross-shore and longshore currents in a parametric and probabilistic mode. In the parametric mode, the computations are based on the root-mean-square wave height, the peak period, and the energy-weighted mean angle of incidence, while in the probabilistic mode a discrete number of classes with their own wave height, period, and angle of incidence is prescribed. Predictions of the two modes differ marginally and result in about the same error statistics when compared to data from laboratory and field experiments. Consistent with other probabilistic wave models, measured wave height distributions inside the surf zone were not reproduced accurately by the present probabilistic model. Although this could be remedied by introducing some variability around the breaker parameter, predictions of the other hydrodynamic parameters did not improve as a result. From a hydrodynamic point of view, it appears superfluous to use the rather time-consuming probabilistic mode for morphodynamic modeling; the parametric mode suffices.