Research On Typhoon Waves Based On Synthetic Aperture Radar And Numerical Simulation

Typhoon wave is the great destructive power generated during the movement of tropical cyclones.In order to reduce the loss caused by typhoon wave,the real-time,high-precision,wide-coverage monitoring and large-scale forecasting of typhoon wave is of great significance.This article is mainly based on synthetic aperture radar and numerical simulation to study typhoon wave.It is mainly divided into three parts: the first part is based on the dual-polarized Sentinel-1 SAR image data to develop typhoon wave inversion algorithms;the second part is based on the WW3 wave model Research on the influence of ocean current on the numerical simulation of typhoon wave;The third part is the analysis of the influence of typhoon path on the distribution of typhoon wave based on the WW3 wave model.For the development of dual-polarized Sentinel-1 SAR image data suitable for typhoon wave inversion algorithm development,this paper mainly collects 8 Sentinel-1dual-polarized SAR images under typhoon(hurricane)condition and the simulation results of WW3 mode to explore the sensitivity relationship between the parameters extracted from the SAR image and the significant wave height is analyzed,and the coefficient fitting of the new CWAVE algorithm is carried out.For the Sentinel-1 SAR data under different imaging modes,two different algorithm fitting coefficients are formed,which greatly improves the accuracy of inverting the significant wave height of the SAR typhoon image.The inversion results are compared with the significant wave height simulated by WW3 and the ECMWF ERA-Interim significant wave height data.The root mean square error of the significant wave height for WW3 is 0.3m,and the root mean square error compared with the ECMWF data is 0.28 m.For the study of the influence of ocean current based on the WW3 wave model on the numerical simulation of typhoon wave,the WW3 wave model was used to analyze the correlation between the typhoon wave and the sea surface current field during Typhoon Talim.It is found that the significant wave height is positively correlated with the velocity of the sea surface flow field,but there is no correlation with several other wave parameters(for example,spectral peak wavelength and spectral peak wave velocity).Moreover,when the velocity of the sea surface current field is greater than 0.5 m/s,the change trend of the sea surface current field is also consistent with the change of the effective wave height and wave steepness rate.However,it is difficult to draw any clear conclusions for the sea surface current velocity below 0.2 m/s.The high wind-sea wave significant wave height area is consistent with the distribution of sea surface current,but the relationship between sea surface current field and swell is weak.For the analysis of the influence of the typhoon path based on the WW3 wave model on the typhoon wave distribution,the wave information of the Northwest Pacific from1998 to 2017 simulated by the WW3 model(version 5.16),and the analysis of the typhoon path from 1998 to 2017 on the Northwest Pacific station Influence of wind and wave distribution.According to typhoon movement and turning point longitude,typhoon tracks are divided into six types of typhoon tracks.The analysis of extracting simulated ocean wave parameters through classified 6 types of typhoon path time shows that the high significant wave height area was moving with the typhoon path changing.The wave is further divided into two parts: wind-sea wave and swell,and it is found that the typhoon path mainly affects the wind-sea wave distribution in the wave.