基于交叉极化数据的海面风速反演研究

摘要

全极化数据可以获取比单极化数据更多的目标信息,研究发现C波段交叉极化数据同样可用于海面风速反演.针对RADARSAT-2 Fine Quad模式具有全极化成像的特点,以我国东部海域为研究区,结合同极化数据和交叉极化数据反演海面风速模型,探究各种极化数据的最优风速反演方法.对于同极化数据采用地球物理模型函数(GMF)和极化率模型(PR)组合的方式进行海面风速反演,对交叉极化数据采用C波段交叉极化海面散射模型(C-2PO)进行海面风速反演,反演结果与ERA-Interim风场数据进行比较分析;此外,对ScanSAR模式交叉极化数据的后向散射系数与海面风速的关系进行探索分析.研究结果表明,RADARSAT-2 Fine Quad模式四种极化数据选用合适的模型均可反演出高精度的海面风速,其中VH和HV极化数据的反演结果基本相同,交叉极化数据反演风速效果好于同极化数据,同时,ScanSAR模式交叉极化数据的后向散射系数随海面风速的增大表现出一定的线性变化趋势.全极化模式数据在海面风速反演上表现出比单极化模式数据较为明显的优势,将成为未来海面风速反演的发展方向.%Full polarization data can get more target information than single polarization data.Research shows that C-band cross-polarization radar data can also be used to retrieve sea surface wind speed.For that RADARSAT-2 Fine Quad mode radar data can obtain full polarization SAR data,the optimal wind speed retrieval models with various polarization data have been discussed by combining with retrieval models of co-polarization and cross-polarization data in the eastern sea area of China.For the copolarization SAR data,sea surface wind speed was retrieved by Geophysical Model Function (GMF) and Polarization Rate (PR) models while for cross-polarization SAR data,it was by C-2PO model,whose retrieved results were compared with ERA-Interim data.Furthermore,the relationship between the NRCS of ScanSAR mode cross-polarization SAR data and sea surface wind speed was also analyzed,whose result shows that the RADRASAT-2 Fine Quad model with appropriate models can all achieve high accuracy of sea surface wind speed,and the cross-polarization data shows better performance than the co-polarization data without requiring the radar incident angle and wind direction.The full polarization mode of RADAR-SAT-2 data shows a significant advantage over the single polarization data,and will become the development direction of sea surface wind speed inversion method in the future.