双频共面合成孔径雷达海面风场反演
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摘要
根据L/C双频共面SAR能够获取同一海域双波段电磁波后向散射系数,得到更多海洋目标特征信息的电磁散射特点,结合地球物理模型函数研究了一种新的SAR海面风场反演方法。利用L/C双频共面SAR的L和C两个波段的地球物理模型函数和后向散射系数等信息,通过地球物理模型函数联立以及构建和求解最小代价函数,直接从SAR数据本身获取海面风场信息,并借助辅助数据去除了风向的180°模糊,从而实现海面风场反演。仿真分析和海上机载同步飞行试验的研究结果表明,该方法可直接利用SAR数据本身获取精度较高的海面风速、风向;绝对辐射定标精度是决定海面风场反演精度的关键因素,海面风场反演误差随定标精度提高而减小;随着海面风速的增大,风速反演误差逐渐增大。论文提出的双频共面SAR海面风场反演方法解决了传统单波段单极化SAR海面风场反演存在的固有问题,机载同步飞行试验的海面风速和风向反演结果与调查船观测值的均方根误差分别为0.93 m/s和19.39°,可为星载SAR海面风场反演业务化和载荷研制提供支持。
In accordance with the ability to obtain further target characteristic information when detecting the same surface area with L/C common reflector dual-frequency SAR dual-band electromagnetic wave, a new ocean wind field retrieval method is proposed.Wind speed and direction are estimated simultaneously using a geophysical model function and a normalized radar cross sections of the L/C dual-band in accordance with a common reflector dual-frequency SAR geophysical model function, and the fuzzy direction of 180° is wiped off using auxiliary data.Verification results show that the wind field retrieval method can be used to retrieve a high-precision wind speed and direction without other background sources in accordance with the simulation and airborne synchronous flight test on a sea. The major error can be explained by the insufficient accuracy in calibrating the NRCS for wind speed and direction retrieval. The wind speed error increases with the value of speed, and the root mean square error of wind speed and direction between retrieval and survey ship observed are 0.93 m/s and 19.39°, respectively.The method for ocean surface wind field retrieval from the common reflector dual-frequency SAR solves the inherent problems of a sea surface wind field inversion of the traditional single-band SAR and increases the retrieval accuracy of the sea surface wind speed and direction, thereby providing support for business application and load developing of an ocean wind field retrieval from space-borne SAR images.
In accordance with the ability to obtain further target characteristic information when detecting the same surface area with L/C common reflector dual-frequency SAR dual-band electromagnetic wave, a new ocean wind field retrieval method is proposed.Wind speed and direction are estimated simultaneously using a geophysical model function and a normalized radar cross sections of the L/C dual-band in accordance with a common reflector dual-frequency SAR geophysical model function, and the fuzzy direction of 180° is wiped off using auxiliary data.Verification results show that the wind field retrieval method can be used to retrieve a high-precision wind speed and direction without other background sources in accordance with the simulation and airborne synchronous flight test on a sea. The major error can be explained by the insufficient accuracy in calibrating the NRCS for wind speed and direction retrieval. The wind speed error increases with the value of speed, and the root mean square error of wind speed and direction between retrieval and survey ship observed are 0.93 m/s and 19.39°, respectively.The method for ocean surface wind field retrieval from the common reflector dual-frequency SAR solves the inherent problems of a sea surface wind field inversion of the traditional single-band SAR and increases the retrieval accuracy of the sea surface wind speed and direction, thereby providing support for business application and load developing of an ocean wind field retrieval from space-borne SAR images.
引文
Ai W H,Kong Y and Zhao X B.2012.Ocean surface wind direction retrieval from multi-polarization airborne SAR based on wavelet.Acta Physica Sinica,61(14):148403(艾未华,孔毅,赵现斌.2012.基于小波的多极化机载合成孔径雷达海面风向反演.物理学报,61(14):148403)[DOI:10.7498/aps.61.148403]
Ai W H,Yan W,Zhao X B,Liu W J and Ma S.2013.A new ocean surface wind field retrieval method from C-band airborne synthetic aperture radar.Acta Physica Sinica,62(6):068401(艾未华,严卫,赵现斌,刘文俊,马烁.2013.C波段机载合成孔径雷达海面风场反演新方法.物理学报,62(6):068401)[DOI:10.7498/aps.62.068401]
Apel J R.1994.An improved model of the ocean surface wave vector spectrum and its effects on radar backscatter.Journal of Geophysical Research Oceans,99(C8):16269-16291[DOI:10.1029/94JC00846]
Cameron I,Lumsdon P,Walker N and Woodhouse I.2006.Advances in SAR oceanography from envisat and ERS missions//Proceedings of SEASAR 2006.Frascati,Italy:ESA Publication Division
De Biasio F and Zecchetto S.2012.Towards the wind direction determination in RADARSAT-2 polarimetrie images.European Journal of Remote Sensing,45(1):141-151[DOI:10.5721/EuJRS20124514]
Horstmann J,Koch W,Lehner S and Tonboe R.2000.Wind retrieval over the ocean using synthetic aperture radar with C-band HH polarization.IEEE Transactions on Geoscience and Remote Sensing,38(5):2122-2131[DOI:10.1109/36.868871]
Hwang P A,Zhang B,Toporkov J V and Perrie W.2010.Comparison of composite Bragg theory and quad-polarization radar backscatter from RADARSAT-2:with applications to wave breaking and high wind retrieval.Journal of Geophysical Research Atmospheres,115(C8):C08019[DOI:10.1029/2009JC005995]
Jiang Z H,Huang S X,He R and Zhou C T.2011a.Regularization method to retrieve synthetic aperture radar sea surface wind.Acta Physica Sinica,60(6):068401(姜祝辉,黄思训,何然,周晨腾.2011a.合成孔径雷达资料反演海面风场的正则化方法研究.物理学报,60(6):068401)
Jiang Z H,Huang S X,Shi H Q,Zhang W and Wang B.2011b.A new research on sea surface wind direction retrieval of synthetic aperture radar image.Acta Physica Sinica,60(10):108402(姜祝辉,黄思训,石汉青,张伟,王彪.2011b.合成孔径雷达图像反演海面风向新方法的研究.物理学报,60(10):108402)[DOI:10.7498/aps.60.108402]
Jordan R L,Huneycutt B L and Werner M.1995.The SIR-C/X-SARsynthetic aperture radar system.IEEE Transactions on Geoscience and Remote Sensing,33(4):829-839[DOI:10.1109/36.406669]
Kawamura H,Shimada T,Shimada M,Kortcheva A and Watabe I.2002.L-band SAR wind-retrieval model function and its application for studies of coastal surface winds and wind waves//IEEE International Geoscience and Remote Sensing Symposium.Toronto,Ontario,Canada:IEEE,3:1884-1886[DOI:10.1109/IGARSS.2002.1026288]
Koch W.2004.Directional analysis of SAR images aiming at wind direction.IEEE Transactions on Geoscience and Remote Sensing,42(4):702-710[DOI:10.1109/TGRS.2003.818811]
Kong Y,Zhao X B,Ai W H,Han D and Xue J.2011.Ocean surface wind field retrieval from airborne SAR imagery based on Mexican-hat wavelet transform.Journal of PLA University of Science and Technology(Natural Science Edition),12(3):301-306(孔毅,赵现斌,艾未华,韩丁,薛剑.2011.基于墨西哥帽小波变换的机载SAR海面风场反演.解放军理工大学学报(自然科学版),12(3):301-306)[DOI:10.3969/j.issn.1009-3443.2011.03.018]
Lehner S,Pleskachevsky A and Bruck M.2012.High-resolution satellite measurements of coastal wind field and sea state.International Journal of Remote Sensing,33(23):7337-7360[DOI:10.1080/01431161.2012.685975]
Leite G C,Ushizima D M,Medeiros F N S and De Lima G G.2010.Wavelet analysis for wind fields estimation.Sensors,10(6):5994-6016[DOI:10.3390/s100605994]
Levy G.1998.Imaging boundary layer roll signatures for climate applications//Proceedings of Sensing and Managing the Environment.1998 IEEE International Geoscience and Remote Sensing.Seattle,WA,USA:IEEE,3:1437-1438[DOI:10.1109/IGARSS.1998.691483]
Martin S.2004.An Introduction to Ocean Remote Sensing.Cambridge:Cambridge University Press:201-207
Monaldo F.2000.The Alaska SAR demonstration and near-real-time synthetic aperture radar winds.Johns Hopkins APL Technical Digest,21(1):75-79
Mouche A A,Collard F,Chapron B,Dagestad K F,Guitton G and Johannessen J A.2012.On the use of Doppler shift for sea surface wind retrieval from SAR.IEEE Transactions on Geoscience and Remote Sensing,50(7):2901-2909[DOI:10.1109/TGRS.2011.2174998]
Portabella M,Stoffelen A and Johannessen J A.2002.Toward an optimal inversion method for synthetic aperture radar wind retrieval.Journal of Geophysical Research Oceans,107(C8):3086[DOI:10.1029/2001JC000925]
Shimada T,Kawamura H and Shimada M.2003.An L-band geophysical model function for SAR wind retrieval using JERS-1 SAR.IEEE Transactions on Geoscience and Remote Sensing,41(3):518-531[DOI:10.1109/TGRS.2003.808836]
Thompson D and Beal R C.2000.Mapping of mesoscale and submesoscale wind fields using synthetic aperture radar.John Hopkins APL Technical Digest,21:58-67
Vachon P W and Dobson F W.1996.Validation of wind vector retrieval from ERS-1 SAR images over the ocean.The Global Atmosphere and Ocean System,5(2):177-187
Vachon P W and Wolfe J.2011.C-band cross-polarization wind speed retrieval.IEEE Geoscience and Remote Sensing Letters,8(3):456-459[DOI:10.1109/LGRS.2010.2085417]
Xia Z G.1996.Applications of multi-frequency,multi-polarization and multi-incident angle SAR systems in urban land use and land cover mapping//1996 International Geoscience and Remote Sensing Symposium.Lincoln,NE,USA:IEEE,4:2310-2314[DOI:10.1109/IGARSS.1996.516971]
Yang J S.2005.SAR Remote Sensing Techniques of Sea Surface Wind,Surface Wave and Internal Wave.Beijing:Ocean Press:31-32(杨劲松.2005.合成孔径雷达海面风场、海浪和内波遥感技术.北京:海洋出版社:31-32)
Yang J S,Huang W G,Zhou C B,Fu B,Shi A Q and Li D L.2001.Coastal ocean surface wind retrieval from SAR imagery.Journal of Remote Sensing,5(1):13-16(杨劲松,黄韦艮,周长宝,傅斌,史爱琴,厉冬玲.2001.合成孔径雷达图像的近岸海面风场反演.遥感学报,5(1):13-16)[DOI:10.11834/jrs.20010103]
Zhang B and Perrie W.2011.Cross-polarized synthetic aperture radar:a new potential measurement technique for hurricanes.Bulletin of the American Meteorological Society,93(4):531-541[DOI:10.1175/BAMS-D-11-00001.1]
Zhang B,Perrie W,Vachon P W,Li X F,Pichel W G,Guo J and He YJ.2012.Ocean vector winds retrieval from C-band fully polarimetric SAR measurements.IEEE Transactions on Geoscience and Remote Sensing,50(11):4252-4261[DOI:10.1109/TGRS.2012.2194157]
Zhang R W,Yan W,Ai W H and Ma S.2011.A method of ocean surface wind direction retrievals for airborne SAR images based on Gabor wavelet transform.Journal of Microwaves,27(5):79-83(张日伟,严卫,艾未华,马烁.2011.基于Gabor小波变换的机载SAR海面风向反演方法.微波学报,27(5):79-83)
Zhao X B,Yan W,Kong Y,Han D and Liu W J.2013.Theoretical research and experimental verification for ocean surface wind vector retrieval from airborne C-band fully polarimetric SAR.Acta Physica Sinica,62(13):138402(赵现斌,严卫,孔毅,韩丁,刘文俊.2013.机载C波段全极化SAR海面风矢量反演理论研究及实验验证.物理学报,62(13):138402)[DOI:10.7498/aps.62.138402]
Ai W H,Yan W,Zhao X B,Liu W J and Ma S.2013.A new ocean surface wind field retrieval method from C-band airborne synthetic aperture radar.Acta Physica Sinica,62(6):068401(艾未华,严卫,赵现斌,刘文俊,马烁.2013.C波段机载合成孔径雷达海面风场反演新方法.物理学报,62(6):068401)[DOI:10.7498/aps.62.068401]
Apel J R.1994.An improved model of the ocean surface wave vector spectrum and its effects on radar backscatter.Journal of Geophysical Research Oceans,99(C8):16269-16291[DOI:10.1029/94JC00846]
Cameron I,Lumsdon P,Walker N and Woodhouse I.2006.Advances in SAR oceanography from envisat and ERS missions//Proceedings of SEASAR 2006.Frascati,Italy:ESA Publication Division
De Biasio F and Zecchetto S.2012.Towards the wind direction determination in RADARSAT-2 polarimetrie images.European Journal of Remote Sensing,45(1):141-151[DOI:10.5721/EuJRS20124514]
Horstmann J,Koch W,Lehner S and Tonboe R.2000.Wind retrieval over the ocean using synthetic aperture radar with C-band HH polarization.IEEE Transactions on Geoscience and Remote Sensing,38(5):2122-2131[DOI:10.1109/36.868871]
Hwang P A,Zhang B,Toporkov J V and Perrie W.2010.Comparison of composite Bragg theory and quad-polarization radar backscatter from RADARSAT-2:with applications to wave breaking and high wind retrieval.Journal of Geophysical Research Atmospheres,115(C8):C08019[DOI:10.1029/2009JC005995]
Jiang Z H,Huang S X,He R and Zhou C T.2011a.Regularization method to retrieve synthetic aperture radar sea surface wind.Acta Physica Sinica,60(6):068401(姜祝辉,黄思训,何然,周晨腾.2011a.合成孔径雷达资料反演海面风场的正则化方法研究.物理学报,60(6):068401)
Jiang Z H,Huang S X,Shi H Q,Zhang W and Wang B.2011b.A new research on sea surface wind direction retrieval of synthetic aperture radar image.Acta Physica Sinica,60(10):108402(姜祝辉,黄思训,石汉青,张伟,王彪.2011b.合成孔径雷达图像反演海面风向新方法的研究.物理学报,60(10):108402)[DOI:10.7498/aps.60.108402]
Jordan R L,Huneycutt B L and Werner M.1995.The SIR-C/X-SARsynthetic aperture radar system.IEEE Transactions on Geoscience and Remote Sensing,33(4):829-839[DOI:10.1109/36.406669]
Kawamura H,Shimada T,Shimada M,Kortcheva A and Watabe I.2002.L-band SAR wind-retrieval model function and its application for studies of coastal surface winds and wind waves//IEEE International Geoscience and Remote Sensing Symposium.Toronto,Ontario,Canada:IEEE,3:1884-1886[DOI:10.1109/IGARSS.2002.1026288]
Koch W.2004.Directional analysis of SAR images aiming at wind direction.IEEE Transactions on Geoscience and Remote Sensing,42(4):702-710[DOI:10.1109/TGRS.2003.818811]
Kong Y,Zhao X B,Ai W H,Han D and Xue J.2011.Ocean surface wind field retrieval from airborne SAR imagery based on Mexican-hat wavelet transform.Journal of PLA University of Science and Technology(Natural Science Edition),12(3):301-306(孔毅,赵现斌,艾未华,韩丁,薛剑.2011.基于墨西哥帽小波变换的机载SAR海面风场反演.解放军理工大学学报(自然科学版),12(3):301-306)[DOI:10.3969/j.issn.1009-3443.2011.03.018]
Lehner S,Pleskachevsky A and Bruck M.2012.High-resolution satellite measurements of coastal wind field and sea state.International Journal of Remote Sensing,33(23):7337-7360[DOI:10.1080/01431161.2012.685975]
Leite G C,Ushizima D M,Medeiros F N S and De Lima G G.2010.Wavelet analysis for wind fields estimation.Sensors,10(6):5994-6016[DOI:10.3390/s100605994]
Levy G.1998.Imaging boundary layer roll signatures for climate applications//Proceedings of Sensing and Managing the Environment.1998 IEEE International Geoscience and Remote Sensing.Seattle,WA,USA:IEEE,3:1437-1438[DOI:10.1109/IGARSS.1998.691483]
Martin S.2004.An Introduction to Ocean Remote Sensing.Cambridge:Cambridge University Press:201-207
Monaldo F.2000.The Alaska SAR demonstration and near-real-time synthetic aperture radar winds.Johns Hopkins APL Technical Digest,21(1):75-79
Mouche A A,Collard F,Chapron B,Dagestad K F,Guitton G and Johannessen J A.2012.On the use of Doppler shift for sea surface wind retrieval from SAR.IEEE Transactions on Geoscience and Remote Sensing,50(7):2901-2909[DOI:10.1109/TGRS.2011.2174998]
Portabella M,Stoffelen A and Johannessen J A.2002.Toward an optimal inversion method for synthetic aperture radar wind retrieval.Journal of Geophysical Research Oceans,107(C8):3086[DOI:10.1029/2001JC000925]
Shimada T,Kawamura H and Shimada M.2003.An L-band geophysical model function for SAR wind retrieval using JERS-1 SAR.IEEE Transactions on Geoscience and Remote Sensing,41(3):518-531[DOI:10.1109/TGRS.2003.808836]
Thompson D and Beal R C.2000.Mapping of mesoscale and submesoscale wind fields using synthetic aperture radar.John Hopkins APL Technical Digest,21:58-67
Vachon P W and Dobson F W.1996.Validation of wind vector retrieval from ERS-1 SAR images over the ocean.The Global Atmosphere and Ocean System,5(2):177-187
Vachon P W and Wolfe J.2011.C-band cross-polarization wind speed retrieval.IEEE Geoscience and Remote Sensing Letters,8(3):456-459[DOI:10.1109/LGRS.2010.2085417]
Xia Z G.1996.Applications of multi-frequency,multi-polarization and multi-incident angle SAR systems in urban land use and land cover mapping//1996 International Geoscience and Remote Sensing Symposium.Lincoln,NE,USA:IEEE,4:2310-2314[DOI:10.1109/IGARSS.1996.516971]
Yang J S.2005.SAR Remote Sensing Techniques of Sea Surface Wind,Surface Wave and Internal Wave.Beijing:Ocean Press:31-32(杨劲松.2005.合成孔径雷达海面风场、海浪和内波遥感技术.北京:海洋出版社:31-32)
Yang J S,Huang W G,Zhou C B,Fu B,Shi A Q and Li D L.2001.Coastal ocean surface wind retrieval from SAR imagery.Journal of Remote Sensing,5(1):13-16(杨劲松,黄韦艮,周长宝,傅斌,史爱琴,厉冬玲.2001.合成孔径雷达图像的近岸海面风场反演.遥感学报,5(1):13-16)[DOI:10.11834/jrs.20010103]
Zhang B and Perrie W.2011.Cross-polarized synthetic aperture radar:a new potential measurement technique for hurricanes.Bulletin of the American Meteorological Society,93(4):531-541[DOI:10.1175/BAMS-D-11-00001.1]
Zhang B,Perrie W,Vachon P W,Li X F,Pichel W G,Guo J and He YJ.2012.Ocean vector winds retrieval from C-band fully polarimetric SAR measurements.IEEE Transactions on Geoscience and Remote Sensing,50(11):4252-4261[DOI:10.1109/TGRS.2012.2194157]
Zhang R W,Yan W,Ai W H and Ma S.2011.A method of ocean surface wind direction retrievals for airborne SAR images based on Gabor wavelet transform.Journal of Microwaves,27(5):79-83(张日伟,严卫,艾未华,马烁.2011.基于Gabor小波变换的机载SAR海面风向反演方法.微波学报,27(5):79-83)
Zhao X B,Yan W,Kong Y,Han D and Liu W J.2013.Theoretical research and experimental verification for ocean surface wind vector retrieval from airborne C-band fully polarimetric SAR.Acta Physica Sinica,62(13):138402(赵现斌,严卫,孔毅,韩丁,刘文俊.2013.机载C波段全极化SAR海面风矢量反演理论研究及实验验证.物理学报,62(13):138402)[DOI:10.7498/aps.62.138402]