Model parameter input files to compare wave-averaged versus wave-resolving XBeach coastal flooding models for coral reef-lined coasts

This data release includes the XBeach input data files used to evaluate the importance of explicitly modeling sea-swell waves for runup. This was examined using a 2D XBeach short wave-averaged (surfbeat, XB-SB) and a wave-resolving (non-hydrostatic, XB-NH) model of Roi-Namur Island on Kwajalein Atoll in the Republic of Marshall Islands. Results show that explicitly modelling the sea-swell component (using XB-NH) provides a better approximation of the observed runup than XB-SB (which only models the time-variation of the sea-swell wave height), despite good model performance of both models on reef flat water levels and wave heights. However, both models under-predict runup peaks. The difference between XB-SB and XB-NH increases for more extreme wave events and higher sea levels, as XB-NH resolves individual waves and therefore captures SS-wave motions in runup. However, for even larger forcing conditions with offshore wave heights of 6 m, the island is flooded in both XB-SB and XB-NH computations, regardless of the sea-swell wave energy contribution. In such cases, XB-SB would be adequate to model flooding depths and extents on the island while requiring 4-5 times less computational effort.
These input files accompany the modeling for following publication: Quataert, E., Storlazzi, C., van Dongeren, A., and McCall, R., 2020, The importance of explicitly modeling sea-swell waves for runup on reef-lined coasts: Coastal Engineering, https://doi.org/10.1016/j.coastaleng.2020.103704