Evolution of wave spectra during sea breeze and tropical cyclone

Abstract

Wave spectral components change with time and through space by receiving energy from wind, through non-linear energy transfer among the spectral components and dissipation due to white-capping and friction. Changes in wave spectra are high during local events like sea-land breeze and extreme events like tropical cyclones (TC). The wave spectral evolution during a sea-land breeze cycle and TC are studied using both measured and modelled data. During a sea-land breeze cycle, the winds are simulated using Weather Research and Forecasting model and waves using the Simulating Waves Nearshore model. Simulated source terms vary according to the intensification and weakening of sea breeze, with energy from wind input having a maximum influence on wave spectra and white-capping having the least. The evolution of wave spectra during the TC using the European Centre for Medium-Range Weather Forecasts ERA-5 reanalysis data shows large spatial and temporal variations. During the TC, large waves are found in the right quadrant to the TC heading direction. TC generated waves are mostly young wind-seas with the youngest of waves found in the left quadrants and the wave-field does not exactly follow the wind field but depends on the velocity of forward motion of TC.