Improvement of double-peaked spectra: Revisiting the combination of the Gaussian and the JONSWAP models

Abstract

The ability of the Gaussian model to represent the primary system in a double-peaked spectrum is examined in comparison to the one regenerated by the JONSWAP model, while for the secondary system the JONSWAP model is implemented. The research is based on two series of measurements in the northern part of the Gulf of Oman (i.e., 2006–2007 and 2016). It is argued that the shape of the Gaussian model near the peak and the limited extension of its right-hand side tail compared to the JONSWAP model increase the performance of calibrated double-peaked spectra. In other words, using the Gaussian model for the primary system contributes to directly improving the representation of the primary system, and indirectly enhancing the description of the secondary one, while the former benefaction is more significant. This resulted in about a 30% increase in the performance of calibrated double-peaked spectra in those dominated by the secondary system. This was over 50% for those dominated by the primary system. Findings suggest that using the Gaussian model for the primary system combined with the JONSWAP model for the secondary one is critical for the appropriate representation of double-peaked spectra, especially for those with overlapped systems.