Wind wave measurements and modelling in a fetch-limited semi-enclosed lagoon

Abstract

The south-west reef lagoon of New Caledonia is a semi-enclosed basin where, on first approximation, dominating sea state component corresponds to locally generated wind waves. This study aims to evaluate the ability of the wave model WAVEWATCH III to simulate wind wave distribution in this particular fetch-limited context, with a given parameterisation. In order to evaluate the consistency of the simulation results, wave parameters were measured in situ by a wave and tide recorder (WTR9 Aanderaa) and by an acoustic Doppler velocimeter (ADV Sontek). This study underlines specific constrains for the deployment of instruments to assess the characteristic parameters of low amplitude and high frequency wind-waves. Special care was taken in the comparison step as, on one hand the wave model did not simulate the propagation of low-frequency oceanic waves inside the lagoon, and on the other hand the measured spectra bear an intrinsic limitation for high frequencies. The approximation of a sea state dominated by wind waves is verified on the study site. The accuracy of the simulation results is discussed with regards to the wind forcing applied to the model.