Assessment and Monitoring of High Sea State Generated by Tropical Cyclones

Based on energy and momentum conservation laws, a new simple 2D parametric model using ray tracing analysis is used to assess high sea states from tropical cyclones (TCs). From self-similar solutions of model equations, different combinations of TC parameters (maximum wind speed, TC radius and translation velocity) are performed and simplified analytical expressions are suggested for robust first-guess estimates of maximal wave length and height. A 2D geophysical model function (TC-wave GMF) is then constructed to map 2D fields for the dominant wave energy, wavelength and direction within the TC area. Results from the full model and simplified expressions are compared to airborne scanning radar altimeter measurements during hurricane Bonnie (1998) and WW3 estimates. Excellent agreement is found for both field measurements and wave spectral numerical model. While the direct model calculations are more accurate and detailed, TC-wave GMF provides useful immediate estimates of wave fields for practical nowcasting and scientific applications.