A 6-h data were obtained from the fifth generation of the European Center for Medium-Range Weather Forecasts (ECMWF) global reanalysis (ERA5) with 0.25° resolution. Since interactions with TCs can modify the synoptic conditions around the storm (Park et al., 2012), the variables were convolved with a box of width 10 and 20 cells. This averaging with 10 cells (2.5°) was used for the analysis based on monthly means and was enough to average out the TC's effects. The 20 cells averaging (5°) was applied for the along track analysis, which being based on instantaneous data, required a larger convolution width.

A comprehensive observational data set was used to examine shoreward propagating semidiurnal internal tides as they shoal, break and run-up as turbulent boluses across the edge of the Australian North West Shelf (NWS), offshore Dampier, during late winter 2013. The measured waveforms and wavefields supported the grouping of events into two distinct categories: (1) pre-; and, (2) post- wave breaking. It was found that the transition from (1) to (2) was marked by the rise of nonlinear steepening (α) and reduction in dispersion (β), both coefficients that parameterize nonlinear wave effects on the Korteweg-de Vries (KdV) equation. We introduced a criterion for wave breaking from the dimensionless parameter (δ) that relates these two terms: wave breaking occurs when δ < 1. In the first group, dispersive effects were dominant to spread energy out of the semidiurnal wave to a dispersive wave packet of short-period internal solitary waves (ISWs). In the second, dispersion was considered small compared to the cumulative effect of nonlinear steepening. Here, the semidiurnal wave built sufficient energy at its rear face to generate wave breaking, which has been known to produce multiple turbulent boluses. Similar observations have not been described for this region during winter months and highlight that the nonlinear internal wave field is an important feature on the NWS throughout the year. Additionally, measurements obtained through autonomous ocean glider profiles revealed some of the post-breaking characteristics that included intensive vertical mixing and transport of dense water and suspended material onshore of the shelf break.

Although ocean surface currents are not accounted for in most wave modeling studies, recent works have demonstrated that ocean circulation features may have a great impact on surface gravity waves. In this case study, we coupled in a one‐way mode the hydrodynamic model Regional Ocean Modeling System (ROMS) and the wave model Simulating WAves Nearshore (SWAN) to study the effect of currents on large wave events (LWEs) produced under the influence of cyclones in south/southeastern Brazil. For the five LWEs studied, chosen due to the distinct importance that current‐to‐wave effects had for the period, the results indicate that the addition of currents on the wave model improved the accuracy of the peaks of significant wave height, generally increasing them (by as much as 27%). The increase in wave height occurred mainly near the shelf edge and slope, where the southwestward‐flowing Brazil Current opposes the dominant direction of cyclone‐generated waves (usually from S/SE to S/SW). Modulation of wave height by currents in the subinertial band explained up to 95% of the total variance of the difference between results with and without ocean currents, and this band was largely related to the Brazil Current. Its near‐inertial counterpart explained up to 22% of the total variance and was primarily due to near‐inertial currents in the region. This study provides, for the first time, conclusive evidence that wave‐current interaction can impact LWEs in south/southeastern Brazil.