Are outstanding spectral solitons indicators for rogue waves in JONSWAP seas?

Abstract

Rogue waves are large individual waves whose height is more than twice of the significant wave height. They have the potential to severely damage offshore structures. For this reason, there is a large interest in characteristing rogue waves. A recent study of rogue waves at a shallow water site in the southern North Sea by Teutsch et al. (2022) has revealed that, at this site, the presence of a large outstanding soliton in the nonlinear Fourier spectrum indicates a high probability of rogue wave occurrence.We are interested to see if this indicator is site specific. Here, we will analyse time series obtained from JONSWAP spectra by the nonlinear Fourier transform (NFT). The NFT enables to decompose a signal into components based on their governing nonlinear evolution equations, i.e. the Korteveg-de Vries (KdV) equation for shallow water waves and the nonlinear Schrödinger (NLS) equation for deep water waves. We will investigate if the outstanding soliton indicator also applies to simulated data in shallow and deep water. We will furthermore propagate time series using the KdV and NLS equations, respectively, in order to check how many non-rogue waves with large outstanding soliton in nonlinear spectrum become rogue waves after propagation.