New Method For The Retrieval Of Ocean Surface Wave And Wind Field From Fully Polarimetric Synthetic Aperture Radar

As a advanced remote sensing detection equipment, Synthetic Aperture Radar(SAR) could provide high resolution、all-weather、all day and all nigth ocean image,which could operate in multi-polarization、multi-incedence angle and muti-band.These advantages are impossible for optical and infrared sensors.So the research on how to retrieve sea surface wind and waves from image is very Practical significance and scientific value.Intend to develop a novel method of ocean wave spectra retrieving with full SAR images based on shape from shading (SFS) combining with numerical simulating,feasibility of the new method is theoretically validated in this paper.This method is applied to high resolution fine-quad polarization mode(HH, VV, VH and HV) C-band RADARSAT-2 SAR imagery, in order to retrieve ocean wave spectra and extract wave parameters.Collocated in situ buoy measurements are used to validate the reliability of this method. Results show that the methodcan reliably estimate wave height, dominant wave period, dominant wave length and dominant wave direction.Subsequently, using RADARSAT-2 polarimetric synthetic aperture radar images and C-2PO model to retrieve and verify sea surface wind field, and compare it with the corresponding buoy data.Based on the C-2PO model, a hybrid ocean surface wind retrieve method is presented in this paper, and use the same SAR image to inverse sea surface wind field. The results shows that hybrid method in the stability of wind speed inversion and accuracy of wind direction inversion due to the C-2PO model.Finally, the role of ocean currents in the SAR retrieve of sea surface wind field has been verified by using 50 fully polarimetric SAR images in situ the HF radar current data as well as buoy datas from National Data Buoy Center(NDBC). The results shows that taking the current velocity into account,the accuracy of SAR inversion of sea surface wind speed increases about 0.2m/s.Considering the current direction,the accuracy of SAR inversion of sea surface wind direction increases about 3°-4°.