Estimating surfzone wave transformation and wave setup from remote sensing data

The spatial distribution of wave roller dissipation is derived from optical remote sensing observations in a laboratory setting and is used to estimate wave transformation and radiation stress forcing through the surfzone. The methodology relies on direct measurements of the size of individual wave breaking rollers in an irregular wave field via remote sensing. The wave roller measurements are used to calculate the roller energy, roller dissipation, and the roller component of the radiation stress. These hydrodynamic quantities then serve as input into the wave energy flux and cross-shore momentum balances in order to derive the wave height transformation and mean water level profiles. The accuracy of the methodology is shown to be very good through comparison with in situ data. In addition, the mean water level profile reproduces the transition zone lag and maximum water level at the most shoreward measuring point. Overall, it is demonstrated that the methodology can be successfully applied to irregular waves and can be used to estimate both wave transformation and radiation stress forcing through the surf zone.