Spectral interpolation of long-travelling predicted waves

If a swell propagating over a long distance is dominant, existing spectral wave models will produce unphysical oscillations in the model-predicted wave height field as a result of finite spectral resolution. This is called the Garden Sprinkler Effect (GSE), which is more apparent with high-accuracy propagation schemes. Here, an interpolation method to remove the GSE is developed. This method involves retrieving the higher-resolution wave spectra from lower-resolution wave spectra that are predicted not from a GSE-alleviating scheme but from a shape-preserving advection scheme, by considering the spatial distribution of spectra. Using this method both the removal of the GSE and the preservation of the spatial distribution of spectral values can be attained almost completely.

► A new interpolation method to remove the Garden Sprinkler Effect is developed.
► Higher-resolution wave spectra from lower-resolution wave spectra are retrieved.
► The spatial distribution of spectral values are preserved.