Research On Wave Information Extraction Method Of Wave Spectrometer Under High Wind Speed

Ocean Wave Spectrometer is a new type of active microwave remote sensing radar for ocean wave information detection,which uses low incidence angle beam to scan the cones of the sea surface.SWIM,the main sensor of Sino-French ocean satellite,is the first satelliteborne Ocean Wave Spectrometer in the world,and its six antenna beams are scanned in the range of 0 °～10 °.First of all,this paper makes a basic introduction to the SWIM,and makes it clear that the scattering model of the Ocean Wave Spectrometer under the condition of low incidence angle is a quasi-mirror scattering model.In terms of the actual situation of SWIM,the detection mechanism and specific parameters of wave spectrum are explained in detail.Secondly,according to the working mechanism of the Ocean Wave Spectrometer,the rainfall radar data carried by the tropical rainfall mapping satellite and the reanalysis data of the European medium-range Weather Forecast Center are selected as the data source for research.Because the resolution of the two is not the same in time and space,in order to obtain the information of backscatter coefficients and wind speed in the same time and space,the trilinear interpolation method is used for spatiotemporal matching,thus the remote sensing synchronous data set is obtained.Thirdly,according to the phenomenon of wave breaking caused by high wind speed,the sea surface area is regarded as the combination of non-wave breaking part and wave breaking part,and the influence of these two parts on radar backscattering is statistically independent of each other.Therefore,with the help of the existing quasi-specular backscattering model of nonwave breaking part and considering the effect of wind-induced backscattering,the scope of application of the model is extended to high wind speed.The model is verified by the measured data of remote sensing synchronous data set.In addition,on the basis of the established backscattering model under the condition of high wind speed,the echo signal of the spectrometer is simulated,and the wave spectrum information is extracted from the echo signal based on the detection mechanism of the spectrometer.Based on the PM wave spectrum,the sea surface is simulated by linear filter method,and then the echo of the spectrometer is obtained according to the radar equation.In the process of extraction,the modulation functions are calculated from the echo power,and then the modulation spectrum is obtained by spectrum estimation,as well as wave spectrum by further calculation,which is compared with the theoretical wave spectrum to verify the accuracy of ocean wave information extraction.Finally,because of the nonlinear relationship between backscattering coefficient and wind speed and effective wave height,the wave information extraction model is established by using data-driven long-term and short-term memory neural network and extreme learning machine method,and the model is verified by remote sensing synchronous data set in view of the fact that the measured backscattering coefficients can be obtained.