Ocean Wave Spectrum Inversion Method Research Based On Polarization SAR Data

The ocean wave is the most common type of ocean wave form,it has a wide range of distribution,the research of the wave theory has a long history.The traditional wave observation is given priority to with buoy,mostly located in the coastal waters and the limited number,range and spatial continuity of the waves in the observation,unable to provide complete wave direction spectrum.Synthetic aperture radar is the only instrument to acquiring the large wave direction spectrum,it has an important scientific significance to study how to accurately and effectively obtain the waves from SAR image information.In this paper,the wave is simulated and the simulation based on composition of the theory of small amplitude wave theory,and the numerical simulation in the linear wave theory respectively on the basis of using the linear superposition method and linear filtering method for simulating the waves.This paper based on the NASA/JPL AIRSAR image data,in the use of circular polarization method calculating azimuth Angle,on the basis of using polarized waves information inversion algorithm of SAR data,without calculating three kinds of modulation transfer function(tilt modulation,fluid mechanics,velocity bunching modulation)modulation spectrum inversion under the condition of the wave slope,and calculate the wave direction parameters.The comparison between the inversion wave parameters and the measured parameters by NDBC buoy shows that the two results agree with each other very well.The difference of wavelength is 1.8 meters and the wave direction is 11.2 °,conforming better to the requirements of wave measurement precision.Show that the algorithm can obtain more accurate wave information without the aid of calculating modulation function.In this paper choose multiple areas from the AIRSAR image to do research,based on the wave spread by the opening deep water area,the results found that,the wave propagation direction and wavelength have a little change.When the waves spread from open deep to shallow waters,due to the coast of refraction effect,the wave propagation direction and skew between submarine contour,wave propagation,great changes have taken place in the direction,which in line with the nearshore wave refraction characteristics.At the same time the waves greatly influenced by the external factors,such as submarine topography,wave refraction,the wave wavelength become shorter.