Energetic Ocean Waves: Numerical Simulations, Real-time Observations and Forecast Improvement

In this work I attempt to unify the three main research topics of energetic ocean waves: numerical simulations, observations, and forecasting. The numerical simulations are completed with two widely used methods –higher-order spectral method (‘HOS’), and the boundary element method (‘BEM’). An investigation into spectra influence on statistical wave properties is carried out. In addition, I investigate the sensible spatial domain size for such simulations. The novel results allow for a reduction in computational costs for future simulations. The limitations of numerical models are addressed. First – incipient wave breaking in higher-order spectral methods is explored. During this exercise breaking onset threshold parameter B ∼ 0.85 is shown to be a good indicator of incipient breaking. In turn, HOS shows itself as a good candidate for future development of a hybrid model that would combine non-breaking, breaking, and broken waves. BEM is used along HOS for additional, independent validation. Recognizing model limitations, I then move on to the possibility of including empirical data into either models themselves, or as model training tools. There is a whole chapter dedicated to available sensors, data acquisition, validations, transmission, and storage. In this chapter I describe a reasonable combination of instruments that would allow for collection of both air and sea data. Since the instrumentation and models are already discussed in depth, I move on to how this combination can be used. Moving from HOS and BEM models, I present forecasting models, and access their accuracy. Next, I present the ‘Wave Obs’ – a new forecast improvement technique, that uses publicly available forecasts and open-source software. I show how the combination of available forecasts, some statistical methods, and wave observations can be used to significantly improve local wave forecast. Moving from daily forecast to prediction of rare events, I present a case of unusual tidal surge activity in summer 2022, in Western Europe. Combining the observations, hindcasts, and mathematical approach I can confirm that this event was a series of meteotsunami events. I then discuss the difficulties in forecasting such events.