The Research Of Retrieving Wave Information From GF-3 SAR Wave Mode Images

Synthetic Aperture Radar is an advanced microwave imaging radar,widely used for imaging specialty in almost any weather conditions.GF-3 satellite provides a large number of new and high quality SAR data for marine environmental monitoring and marine scientific research.So the wave information retrieval from GF-3 SAR images is beneficial for scientific research and commerce.In this paper,the development of SAR satellites and current situation of wave research were reviewed firstly,ocean remote sensing concept and SAR imaging mechanism were also combed at the same time.Then we do the further research on wave information retrieval method development and improvement on the basis of predecessors' research.A significant wave height empirical retrieval from GF-3 SAR wave mode image was present,developed from empirical function about radar incidence,HH HV and VV polarization normalized radar cross section,normalized variance of images,azimuth Cut-Off,peak wavelength and direction.Validation of SWH retrieval from SAR images for six incidence angle mode was done,using QPCWAVE_GF3 model,compared with WW3 data,altimeter and buoy SWH data.Results show there was little variety on inversion accuracy for six incidence angle mode,with an RMSE of0.55 m,a SI of 20% and a correlation coefficient of 0.85.And it may reveal the fact that lower incidence angle mode are more favorable for SAR ocean wave height retrieval.Finally,a discussion of cross-polarization NRCS contribution to SWH empirical model was done,and it reveal the fact that cross-polarization NRCS can improve model inversion accuracy,especially in high sea conditions.In this paper,a wave information retrieval from SAR images was developed,which ensured size of Lee filter window by estimating local sea conditions using QPCWAVE_GF3 model,estimated wave slope and wave spectra from SAR images and acquired wave parameters from wave slope spectra,compared retrieved results with in-situ buoy data finally.Results show that the inversion accuracy of wavelength,wave period and wave direction and the integral accuracy are fine.However,compared with under middle sea condition,accuracy under low and high sea conditions need to improved.