Abstract: Ocean waves generated by tropical cyclones are an important manifestation of air-sea interaction, and their generation mechanisms and evolution patterns represent one of the frontier topics in physical oceanography. In this study, using sea surface wind speed observations from the Soil Moisture Active/Passive (SMAP) L-band microwave radiometer and spatiotemporally matched significant wave height data from the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis (ERA5), we systematically analyzed 40 tropical cyclone cases in the Northern Hemisphere and developed a quadratic polynomial wind-wave correlation model that integrates cyclone dynamic parameters with azimuthally continuous corrections. First, by analyzing the 40 Northern Hemisphere tropical cyclone cases from 2015 to 2023, we found that the maximum significant wave heights predominantly occur near the radius of maximum wind speed and are concentrated at approximately 105° to the right of the moving direction, while the minimum values are concentrated at approximately 270° behind the moving path. On this basis, we introduced three empirical parameters—residence time, wind field intensity factor, and normalized radius—and constructed an initial quadratic polynomial wind-wave model using sea surface wind speed data. To address the azimuthal dependence of the model residuals, a third-order Fourier series was employed to further correct the model, and an exponential function was introduced to correct the overall nonlinear errors. Comparative validation results show that the new model achieves a correlation coefficient of 0.89, a root mean square error of 0.96 m, and a mean error of 0.04 m when compared with significant wave height data from the National Data Buoy Center (NDBC) buoys. Furthermore, compared with traditional empirical fitting methods based on quadrant division, the new model demonstrates higher accuracy in describing the spatial distribution of significant wave height and its azimuthally continuous variations.

Key words: significant wave height, ERA5, SMAP satellite-borne radiometer, wind-wave growth model