TRIADS: A phase-resolving model for nonlinear shoaling of directional wave spectra

•First numerical implementation of a directional triad interaction model for nonlinear shoaling of broad wave spectra.•Comprehensive analysis of nonlinear mechanisms for sum and difference interaction of directional wave.•Extensive numerical-data comparison for shoaling waves during Hurricane Bill.

We investigate the performance of TRIADS, a numerical implementation of a phase-resolving, nonlinear, spectral model describing directional wave evolution in intermediate and shallow water. TRIADS simulations of shoaling waves generated by Hurricane Bill, 2009 are compared to directional spectral estimates based on observations collected at the Field Research Facility of the US Army Corps Of Engineers, at Duck, NC. Both the ability of the model to capture the processes essential to the nonlinear wave evolution, and the efficiency of the numerical implementations are analyzed and discussed.