各向异性海面全极化微波双站散射的仿真与分析
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摘要
为了解各向异性随机粗糙海面的微波双站散射机制及其特性,本文利用解析近似的积分方程模型以及一种改进的半经验海浪谱模型实现了对各向异性随机粗糙海面的全极化微波散射仿真模拟,并与卫星观测数据、经验的地球物理模式函数及已有的解析近似散射模型仿真结果进行了对比,验证了仿真结果的可行性和准确性。利用该模型分析了入射波频率、入射角、极化方式、海面风速及风向等参数对各向异性海面双站散射的影响。模拟结果表明,在不同的入射角、散射角及方位角等观测几何条件下,海面不同波段的双站散射表现出不同的空间散射特性,且对风速、风向等海面动力学参数表现出不同的敏感性,以L波段为例,海面向后半球双站散射在各个极化方式下都对风速较为敏感,而在同极化方式下,其对风向的响应在中低风速和高风速条件下相反,整体而言,低风速下海面双站散射对风向更为敏感。这表明对于海面动力参数的反演,双站散射可以提供比传统单站雷达后向散射更丰富的物理信息。本文探讨了各向异性海面微波双站散射特性,为基于主动式及分布式微波传感器的海洋动力参数遥感反演提供了理论分析基础。
In order to explore the possibilities of ocean geophysical parameter retrievals with bistatic scattering signals, thorough understanding of ocean bistatic scattering, both its spatial feature and sensitivity to geophysical parameters, will be crucial and meaningful. In this study, the integral equation model(IEM) combined with an improved directional sea spectrum are adopted to simulate the fully polarimetric microwave bistatic scattering from an anisotropic ocean surface. By comparing the simulation results with satellite observations, the geophysical model function CMOD5 and the simulations of Small Slope Approximation(SSA), the practicability of proposed method in simulating ocean surface microwave scattering is validated. Furthermore, the sensitivities of sea surface bistatic scattering to several geometric and physical parameters, i.e., microwave frequency, incidence, polarization, wind speed and direction, are investigated with this method. The simulation results indicate that ocean surface bistatic scatterings show different spatial scattering characteristics under different observation geometry, and have various sensitivities to ocean dynamic parameters, namely, wind speed and wind direction. Specifically, L-band bistatic scatterings in the backward directions are more sensitive to sea surface wind speed, and the co-polarized ones have opposite responses to wind direction changes for low and high wind speed. At low wind speeds, L-band ocean surface bistatic scatterings have higher sensitivities to wind direction. It is also found that the bistatic scattering contains more spatial information than the conventional monostatic scattering. This work expands the understanding of ocean surface scattering in fully bistatic configuration and explore the potential of parameter retrieval with bistatic radar observations.
In order to explore the possibilities of ocean geophysical parameter retrievals with bistatic scattering signals, thorough understanding of ocean bistatic scattering, both its spatial feature and sensitivity to geophysical parameters, will be crucial and meaningful. In this study, the integral equation model(IEM) combined with an improved directional sea spectrum are adopted to simulate the fully polarimetric microwave bistatic scattering from an anisotropic ocean surface. By comparing the simulation results with satellite observations, the geophysical model function CMOD5 and the simulations of Small Slope Approximation(SSA), the practicability of proposed method in simulating ocean surface microwave scattering is validated. Furthermore, the sensitivities of sea surface bistatic scattering to several geometric and physical parameters, i.e., microwave frequency, incidence, polarization, wind speed and direction, are investigated with this method. The simulation results indicate that ocean surface bistatic scatterings show different spatial scattering characteristics under different observation geometry, and have various sensitivities to ocean dynamic parameters, namely, wind speed and wind direction. Specifically, L-band bistatic scatterings in the backward directions are more sensitive to sea surface wind speed, and the co-polarized ones have opposite responses to wind direction changes for low and high wind speed. At low wind speeds, L-band ocean surface bistatic scatterings have higher sensitivities to wind direction. It is also found that the bistatic scattering contains more spatial information than the conventional monostatic scattering. This work expands the understanding of ocean surface scattering in fully bistatic configuration and explore the potential of parameter retrieval with bistatic radar observations.
引文
[1] Apel J R. An improved model of the ocean surface wave vector spectrum and its effects on radar backscatter[J]. Journal of Geophysical Research: Oceans, 1994, 99(C8): 16269-16291.
[2] Carvajal G K, Eriksson L E B, Ulander L M H. Retrieval and quality assessment of wind velocity vectors on the ocean with C-band SAR[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(5): 2519-2537.
[3] 杜延磊, 马文韬, 杨晓峰, 等. 无云情况下L波段微波辐射计快速大气校正方法[J]. 物理学报, 2015, 64(7): 079501. Du Yanlei, Ma Wentao, Yang Xiaofeng, et al. A rapid atmospheric correction model for L-band microwave radiometer under the cloudless condition[J]. Acta Physica Sinica, 2015, 64(7): 079501.
[4] Elfouhaily T, Chapron B, Katsaros K, et al. A unified directional spectrum for long and short wind-driven waves[J]. Journal of Geophysical Research: Oceans, 1997, 102(C7): 15781-15796.
[5] Yang Xiaofeng, Li Xiaofeng, Pichel W G, et al. Comparison of ocean surface winds from ENVISAT ASAR, MetOp ASCAT scatterometer, buoy measurements, and NOGAPS model[J]. IEEE Transactions on Geoscience and Remote Sensing, 2011, 49(12): 4743-4750.
[6] 郭立新, 王蕊, 吴振森. 随机粗糙面散射的基本理论与方法[M]. 北京: 科学出版社, 2010: 32-61. Guo Lixin, Wang Rui, Wu Zhensen. Basic Theory and Method of Random Rough Surface Scattering[M]. Beijing: Science Press, 2010: 32-61.
[7] 罗伟. 时变海面与目标复合电磁散射研究[D]. 西安: 西安电子科技大, 2011. Luo Wei. A study of electromagnetic composite scattering from the time-varied sea surfaces and targets[D]. Xi'an: Xidian University, 2011.
[8] Fung A K, Lee K. A semi-empirical sea-spectrum model for scattering coefficient estimation[J]. IEEE Journal of Oceanic Engineering, 1982, 7(4): 166-176.
[9] Kudryavtsev V, Hauser D, Caudal G, et al. A semiempirical model of the normalized radar cross section of the sea surface, 2. Radar modulation transfer function[J]. Journal of Geophysical Research: Oceans, 2003, 108(C3): FET 3-1-FET 3-16.
[10] Yueh S H, Tang Wenqing, Fore A G, et al. L-band passive and active microwave geophysical model functions of ocean surface winds and applications to aquarius retrieval[J]. IEEE Transactions on Geoscience and Remote Sensing, 2013, 51(9): 4619-4632.
[11] Du Yanlei, Yang Xiaofeng, Chen Kunshan, et al. An improved spectrum model for sea surface radar backscattering at L-Band[J]. Remote Sensing, 2017, 9(8), 776.
[12] Bruce N C, Dainty J C. Multiple scattering from random rough surfaces using the kirchhoff approximation[J]. Journal of Modern Optics, 1991, 38(3): 579-590.
[13] Soto-Crespo J M, Nieto-Vesperinas M, Friberg A T. Scattering from slightly rough random surfaces: a detailed study on the validity of the small perturbation method[J]. Journal of the Optical Society of America A, 1990, 7(7): 1185-1201.
[14] Khenchaf A, Daout F, Saillard J. The two-scale model for random rough surface scattering[C]//Proceedings of the OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean-Prospects for the 21st Century. Fort Lauderdale, FL, USA: IEEE, 1996: 887-891.
[15] Voronovich A. Small-Slope Approximation for electromagnetic wave scattering at a rough interface of two dielectric half-spaces[J]. Waves in Random Media, 1994, 4(3): 337-367.
[16] Fung A K, Li Zongqian, Chen Kunshan. Backscattering from a randomly rough dielectric surface[J]. IEEE Transactions on Geoscience and Remote Sensing, 1992, 30(2): 356-369.
[17] Chen K S, Wu T D, Tsang L, et al. Emission of rough surfaces calculated by the integral equation method with comparison to three-dimensional moment method Simulations[J]. IEEE Transactions on Geoscience and Remote Sensing, 2003, 41(1): 90-101.
[18] Chen Kunshan, Fung A K, Weissman D A. A backscattering model for ocean surface[J]. IEEE Transactions on Geoscience and Remote Sensing, 1992, 30(4): 811-817.
[19] Fung A K, Zuffada C, Hsieh C Y. Incoherent bistatic scattering from the sea surface at L-band[J]. IEEE Transactions on Geoscience and Remote Sensing, 2001, 39(5): 1006-1012.
[20] Xu Feng, Li Xiaofeng, Wang Peng, et al. A backscattering model of rainfall over rough sea surface for synthetic aperture radar[J]. IEEE Transactions on Geoscience and Remote Sensing, 2015, 53(6): 3042-3054.
[21] Krieger G. MIMO-SAR: opportunities and pitfalls[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(5): 2628-2645.
[22] Awada A, Ayari M Y, Khenchaf A, et al. Bistatic scattering from an anisotropic sea surface: numerical comparison between the first-order SSA and the TSM models[J]. Waves in Random and Complex Media, 2006, 16(3): 383-394.
[23] Ayari M Y, Khenchaf A, Coatanhay A. Simulations of the bistatic scattering using two-scale model and the unified sea spectrum[J]. Journal of Applied Remote Sensing, 2007, 1(1): 013532.
[24] Sancer M I. Shadow-corrected electromagnetic scattering from a randomly rough surface[J]. IEEE Transactions on Antennas and Propagation, 1969, 17(5): 577-585.
[25] Ghanmi H, Khenchaf A, Comblet F. Bistatic scattering from a contaminated sea surface observed in C, X, and Ku bands[C]//Proceedings Volume 9240, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2014. Amsterdam, Netherlands: SPIE, 2014: 924009.
[26] Wu T D, Chen Kunshan, Shi Jiancheng, et al. A study of an AIEM model for bistatic scattering from randomly rough surfaces[J]. IEEE Transactions on Geoscience and Remote Sensing, 2008, 46(9): 2584-2598.
[27] Gustafsson M, Herberthson M, Rahm J, et al. A new methodology for measuring the bistatic ground scattering coefficient. Comparisons with the AIEM at large bistatic angles[J]. IEEE Geoscience and Remote Sensing Letters, 2013, 10(5): 1167-1170.
[28] Hersbach H, Stoffelen A, de Haan S. An improved C-band scatterometer ocean geophysical model function: CMOD5[J]. Journal of Geophysical Research: Oceans, 2007, 112(C3): C03006.
[29] Thompson D R, Elfouhaily T M, Chapron B. Polarization ratio for microwave backscattering from the ocean surface at low to moderate incidence angles[C]//Proceedings of the IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. Seattle, WA, USA: IEEE, 1998: 1671-1673.
[30] Hajj G A, Zuffada C. Theoretical description of a bistatic system for ocean altimetry using the GPS signal[J]. Radio Science, 2003, 38(5): 1089.
[2] Carvajal G K, Eriksson L E B, Ulander L M H. Retrieval and quality assessment of wind velocity vectors on the ocean with C-band SAR[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(5): 2519-2537.
[3] 杜延磊, 马文韬, 杨晓峰, 等. 无云情况下L波段微波辐射计快速大气校正方法[J]. 物理学报, 2015, 64(7): 079501. Du Yanlei, Ma Wentao, Yang Xiaofeng, et al. A rapid atmospheric correction model for L-band microwave radiometer under the cloudless condition[J]. Acta Physica Sinica, 2015, 64(7): 079501.
[4] Elfouhaily T, Chapron B, Katsaros K, et al. A unified directional spectrum for long and short wind-driven waves[J]. Journal of Geophysical Research: Oceans, 1997, 102(C7): 15781-15796.
[5] Yang Xiaofeng, Li Xiaofeng, Pichel W G, et al. Comparison of ocean surface winds from ENVISAT ASAR, MetOp ASCAT scatterometer, buoy measurements, and NOGAPS model[J]. IEEE Transactions on Geoscience and Remote Sensing, 2011, 49(12): 4743-4750.
[6] 郭立新, 王蕊, 吴振森. 随机粗糙面散射的基本理论与方法[M]. 北京: 科学出版社, 2010: 32-61. Guo Lixin, Wang Rui, Wu Zhensen. Basic Theory and Method of Random Rough Surface Scattering[M]. Beijing: Science Press, 2010: 32-61.
[7] 罗伟. 时变海面与目标复合电磁散射研究[D]. 西安: 西安电子科技大, 2011. Luo Wei. A study of electromagnetic composite scattering from the time-varied sea surfaces and targets[D]. Xi'an: Xidian University, 2011.
[8] Fung A K, Lee K. A semi-empirical sea-spectrum model for scattering coefficient estimation[J]. IEEE Journal of Oceanic Engineering, 1982, 7(4): 166-176.
[9] Kudryavtsev V, Hauser D, Caudal G, et al. A semiempirical model of the normalized radar cross section of the sea surface, 2. Radar modulation transfer function[J]. Journal of Geophysical Research: Oceans, 2003, 108(C3): FET 3-1-FET 3-16.
[10] Yueh S H, Tang Wenqing, Fore A G, et al. L-band passive and active microwave geophysical model functions of ocean surface winds and applications to aquarius retrieval[J]. IEEE Transactions on Geoscience and Remote Sensing, 2013, 51(9): 4619-4632.
[11] Du Yanlei, Yang Xiaofeng, Chen Kunshan, et al. An improved spectrum model for sea surface radar backscattering at L-Band[J]. Remote Sensing, 2017, 9(8), 776.
[12] Bruce N C, Dainty J C. Multiple scattering from random rough surfaces using the kirchhoff approximation[J]. Journal of Modern Optics, 1991, 38(3): 579-590.
[13] Soto-Crespo J M, Nieto-Vesperinas M, Friberg A T. Scattering from slightly rough random surfaces: a detailed study on the validity of the small perturbation method[J]. Journal of the Optical Society of America A, 1990, 7(7): 1185-1201.
[14] Khenchaf A, Daout F, Saillard J. The two-scale model for random rough surface scattering[C]//Proceedings of the OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean-Prospects for the 21st Century. Fort Lauderdale, FL, USA: IEEE, 1996: 887-891.
[15] Voronovich A. Small-Slope Approximation for electromagnetic wave scattering at a rough interface of two dielectric half-spaces[J]. Waves in Random Media, 1994, 4(3): 337-367.
[16] Fung A K, Li Zongqian, Chen Kunshan. Backscattering from a randomly rough dielectric surface[J]. IEEE Transactions on Geoscience and Remote Sensing, 1992, 30(2): 356-369.
[17] Chen K S, Wu T D, Tsang L, et al. Emission of rough surfaces calculated by the integral equation method with comparison to three-dimensional moment method Simulations[J]. IEEE Transactions on Geoscience and Remote Sensing, 2003, 41(1): 90-101.
[18] Chen Kunshan, Fung A K, Weissman D A. A backscattering model for ocean surface[J]. IEEE Transactions on Geoscience and Remote Sensing, 1992, 30(4): 811-817.
[19] Fung A K, Zuffada C, Hsieh C Y. Incoherent bistatic scattering from the sea surface at L-band[J]. IEEE Transactions on Geoscience and Remote Sensing, 2001, 39(5): 1006-1012.
[20] Xu Feng, Li Xiaofeng, Wang Peng, et al. A backscattering model of rainfall over rough sea surface for synthetic aperture radar[J]. IEEE Transactions on Geoscience and Remote Sensing, 2015, 53(6): 3042-3054.
[21] Krieger G. MIMO-SAR: opportunities and pitfalls[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(5): 2628-2645.
[22] Awada A, Ayari M Y, Khenchaf A, et al. Bistatic scattering from an anisotropic sea surface: numerical comparison between the first-order SSA and the TSM models[J]. Waves in Random and Complex Media, 2006, 16(3): 383-394.
[23] Ayari M Y, Khenchaf A, Coatanhay A. Simulations of the bistatic scattering using two-scale model and the unified sea spectrum[J]. Journal of Applied Remote Sensing, 2007, 1(1): 013532.
[24] Sancer M I. Shadow-corrected electromagnetic scattering from a randomly rough surface[J]. IEEE Transactions on Antennas and Propagation, 1969, 17(5): 577-585.
[25] Ghanmi H, Khenchaf A, Comblet F. Bistatic scattering from a contaminated sea surface observed in C, X, and Ku bands[C]//Proceedings Volume 9240, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2014. Amsterdam, Netherlands: SPIE, 2014: 924009.
[26] Wu T D, Chen Kunshan, Shi Jiancheng, et al. A study of an AIEM model for bistatic scattering from randomly rough surfaces[J]. IEEE Transactions on Geoscience and Remote Sensing, 2008, 46(9): 2584-2598.
[27] Gustafsson M, Herberthson M, Rahm J, et al. A new methodology for measuring the bistatic ground scattering coefficient. Comparisons with the AIEM at large bistatic angles[J]. IEEE Geoscience and Remote Sensing Letters, 2013, 10(5): 1167-1170.
[28] Hersbach H, Stoffelen A, de Haan S. An improved C-band scatterometer ocean geophysical model function: CMOD5[J]. Journal of Geophysical Research: Oceans, 2007, 112(C3): C03006.
[29] Thompson D R, Elfouhaily T M, Chapron B. Polarization ratio for microwave backscattering from the ocean surface at low to moderate incidence angles[C]//Proceedings of the IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. Seattle, WA, USA: IEEE, 1998: 1671-1673.
[30] Hajj G A, Zuffada C. Theoretical description of a bistatic system for ocean altimetry using the GPS signal[J]. Radio Science, 2003, 38(5): 1089.
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