Extreme Wave Analysis Based on 31 Years Data from WW3 Model: Study off Southern Brazilian Coast

Abstract A long-term wave hindcast (1979-2009) based on the NCEP/NCAR Reanalysis and WAVEWATCH III has been assessed using 29 months of wave measurements over Rio Grande shelf, South Brazil to evaluate the skills and biases in the wave hindcast for this region. Extreme events were selected by Peaks Over Thresholds (POT) and fitted by a Generalized Pareto Distribution (GPD) to estimate the extreme significant wave height from the 31 years wave simulation. The significant wave heights from the hinhindcast and measurement show generally good aagreement although the wave heights tended to be underestimated in the hindcast. This underestimation was more pronounced in extreme wave events. The estimated extreme waves, based on a hindcast, with 50 and 100 years return period in the offshore deep water over the Rio Grande shelf, feature large waves heights with 10.54 and 11.18 meters, respectively. The information presented here can be useful for those involved in coastal management and disaster response and also for the navigation and offshore operations.