THE PHYSICAL PROCESSES ACTIVE IN TROPOCAL CYCLONE WAVE GENERATION

Abstract

In tropical and subtropical regions tropical cyclones represent the major extreme meteorological events, generating winds in excess of 40m/s and significant wave heights above 10m. Such systems are characterized by a well-formed translating vortex wind field with a calm eye and winds that spiral in toward the center of the storm. Despite the apparent complexity of the forcing wind field, observations of waves in tropical cyclones show that there are many similarities to waves generated in relatively simple cases with approximately constant unidirectional winds (Tamizi and Young 2020. It has often been speculated (Tamizi and Young 2020) that this is because nonlinear wave–wave interactions play a dominate role in defining the tropical cyclone directional wave spectrum and hence the significant wave height, as they do for more simple wave generation cases. Despite this speculation and the many observational studies of tropical cyclone wave spectra, no study has yet been able to demonstrate the role of nonlinear wave–wave interactions in tropical cyclones. Firstly, the observational database from buoys and remote sensing systems are summarized. A third generation spectral wave model is then used to model typical tropical cyclones and the role played by each of wind input, dissipation and nonlinear interactions is investigated in detail.