volume | PIER Journals

Abstract

Electromagnetic scattering from time-varying sea surfaces under right-hand circularly polarized (RHCP) wave incidence is investigated, with emphasis on exploring the influence of nonlinear hydrodynamic interactions on Doppler spectral signatures as well as on examining the polarization difference of Doppler spectra between right-hand and left-hand polarized scattering waves. The choppy wave model (CWM) is adopted for describing nonlinear hydrodynamic interactions between ocean waves, and it is constructed by adding horizontal displacements through performing Hilbert transform for a reference linear surface model. Simulation results show that Doppler spectral signatures are significantly influenced by nonlinear hydrodynamic interactions in particular in low-grazing angle regime. It is also indicated that Doppler spectral signatures show distinct polarization dependence. In addition, numerical simulations show that Doppler shift of left-hand polarized scattering wave increases obviously with wind speed increasing, whereas the Doppler shift of right-hand polarized scattering wave looks less sensitive to wind speed variations. The result is potentially valuable in remote sensing applications with Global Navigation Satellite System-Reflectometry (GNSS-R) signals.

1. Alpers, W., A. Mouche, J. Horstmann, A. Y. Ivanov, and V. S. Barabanov, "Application of a new algorithm using Doppler information to retrieve complex wind fields over the Black Sea from ENVISAT SAR images," Int. J. Remote Sens., Vol. 36, No. 3, 863-881, 2015.
doi:10.1080/01431161.2014.999169

2. Hisaki, Y., "Nonlinear inversion of the integral equation to estimate ocean wave spectra from HF radar," Radio Sci., Vol. 31, No. 1, 25-39, 1996.
doi:10.1029/95RS02439

3. Hwang, P. A., M. A. Sletten, and J. V. Toporkov, "A note on Doppler processing of coherent radar backscatter from the water surface: With application to ocean surface wave measurements," J. Geophys. Res., Vol. 115, No. C03026, 2010.

4. Brau, N., F. Ziemer, A. Bezuglov, M. Cysewski, and G. Schymura, "Sea-surface current features observed by Doppler radar," IEEE Trans. Geosci. Remote Sensing, Vol. 46, No. 4, 1125-1133, 2008.
doi:10.1109/TGRS.2007.910221

5. Fois, F., P. Hoogeboom, F. Le Chevalier, A. Stoffelen, and A. Mouche, "Dopscat: A mission concept for simultaneous measurements of marine winds and surface currents," J. Geophys. Res., Vol. 120, No. 12, 7857-7879, 2015.
doi:10.1002/2015JC011011

6. Barrick, D. E. and J. B. Snider, "The statistics of HF sea-echo Doppler spectra," IEEE Trans. Antennas Propag., Vol. 25, No. 1, 19-28, 1977.
doi:10.1109/TAP.1977.1141529

7. Crombie, D. D., "Doppler spectrum of sea echo at 13.56 mc/s," Nature, Vol. 175, No. 4459, 681-682, 1955.
doi:10.1038/175681a0

8. Lee, P. H. Y., J. D. Barter, K. L. Beach, C. L. Hindman, B. M. Lake, H. Rungaldier, J. C. Shelton, A. B. Williams, R. Yee, and H. C. Yuen, "X band microwave backscattering from ocean waves," J. Geophys. Res., Vol. 100, No. C2, 2591-2611, 1995.
doi:10.1029/94JC02741

9. Nouguier, F., C.-A. Gurin, and G. Soriano, "Analytical techniques for the Doppler signature of sea surfaces in the microwave regime --- I: Linear surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 49, No. 12, 4856-4864, 2011.
doi:10.1109/TGRS.2011.2152848

10. Pidgeon, V. W., "Doppler dependence of radar sea return," J. Geophys. Res., Vol. 73, No. 4, 1333-1341, 1968.
doi:10.1029/JB073i004p01333

11. Plant, W. J., "A model for microwave Doppler sea return at high incidence angles: Bragg scattering from bound, tilted waves," J. Geophys. Res., Vol. 102, No. C9, 21131-21146, 1997.
doi:10.1029/97JC01225

12. Soriano, G., M. Joelson, and M. Saillard, "Doppler spectra from a two-dimensional ocean surface at L-band," IEEE Trans. Geosci. Remote Sensing, Vol. 44, No. 9, 2430-2437, 2006.
doi:10.1109/TGRS.2006.873580

13. Toporkov, J. V. and G. S. Brown, "Numerical simulations of scattering from time-varying, randomly rough surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 38, No. 4, 1616-1625, 2000.
doi:10.1109/36.851961

14. Yurovsky, Y. Y., V. N. Kudryavtsev, B. Chapron, and S. A. Grodsky, "Modulation of Ka-band Doppler radar signals backscattered from the sea surface," IEEE Trans. Geosci. Remote Sensing, Vol. 56, No. 5, 2931-2948, 2018.
doi:10.1109/TGRS.2017.2787459

15. Zavorotny, V. U. and A. G. Voronovich, "Two-scale model and ocean radar Doppler spectra at moderate- and low-grazing angles," IEEE Trans. Antennas Propag., Vol. 46, No. 1, 84-92, 1998.
doi:10.1109/8.655454

16. Plant, W. J. and G. Farquharson, "Wave shadowing and modulation of microwave backscatter from the ocean," J. Geophys. Res., Vol. 117, No. C8, C08010, 2012.
doi:10.1029/2012JC007912

17. Hayslip, A. R., J. T. Johnson, and G. R. Baker, "Further numerical studies of backscattering from time-evolving nonlinear sea surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 41, No. 10, 2287-2293, 2003.
doi:10.1109/TGRS.2003.814662

18. Miret, D., G. Soriano, F. Nouguier, P. Forget, M. Saillard, and C.-A. Gurin, "Sea surface microwave scattering at extreme grazing angle: Numerical investigation of the Doppler shift," IEEE Trans. Geosci. Remote Sensing, Vol. 52, No. 11, 7120-7129, 2014.
doi:10.1109/TGRS.2014.2307893

19. Creamer, D. B., F. Henyey, R. Schult, and J. Wright, "Improved linear representation of ocean surface waves," J. Fluid Mech., Vol. 205, 135-161, 1989.
doi:10.1017/S0022112089001977

20. Nouguier, F., C.-A. Gurin, and B. Chapron, "`Choppy wave' model for nonlinear gravity waves," J. Geophys. Res., Vol. 114, No. C9, C09012, 2009.
doi:10.1029/2008JC004984

21. West, B. J., K. A. Brueckner, R. S. Janda, D. M. Milder, and R. L. Milton, "A new numerical method for surface hydrodynamics," J. Geophys. Res., Vol. 92, No. C11, 11803-11824, 1987.
doi:10.1029/JC092iC11p11803

22. Wang, Y. H., Y. M. Zhang, M. X. He, and C. F. Zhao, "Doppler spectra of microwave scattering fields from nonlinear oceanic surface at moderate- and low-grazing angles," IEEE Trans. Geosci. Remote Sensing, Vol. 50, No. 4, 1104-1116, 2012.
doi:10.1109/TGRS.2011.2164926

23. Luo, G. and M. Zhang, "Investigation on the scattering from one-dimensional nonlinear fractal sea surface by second-order small-slope approximation," Progress In Electromagnetics Research, Vol. 133, 425-441, 2013.
doi:10.2528/PIER12082706

24. Johnson, J. T., J. V. Toporkov, and G. S. Brown, "A numerical study of backscattering from time evolving sea surfaces: Comparison of hydrodynamic models," IEEE Trans. Geosci. Remote Sensing, Vol. 39, No. 11, 2411-2420, 2001.
doi:10.1109/36.964977

25. Rino, C. L., T. L. Crystal, A. K. Koide, H. D. Ngo, and H. Guthart, "Numerical simulation of backscatter from linear and nonlinear ocean surface realizations," Radio Sci., Vol. 26, No. 1, 51-71, 1991.
doi:10.1029/90RS01687

26. Fois, F., P. Hoogeboom, F. L. Chevalier, and A. Stoffelen, "An analytical model for the description of the full-polarimetric sea surface Doppler signature," J. Geophys. Res., Vol. 120, No. 2, 988-1015, 2015.
doi:10.1002/2014JC010589

27. Li, X. F. and X. J. Xu, "Scattering and Doppler spectral analysis for two-dimensional linear and nonlinear sea surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 49, No. 2, 603-611, 2011.
doi:10.1109/TGRS.2010.2060204

28. Nie, D., M. Zhang, C. Wang, and H. C. Yin, "Study of microwave backscattering from two dimensional nonlinear surfaces of finite-depth seas," IEEE Trans. Geosci. Remote Sensing, Vol. 50, No. 11, 4349-4357, 2012.
doi:10.1109/TGRS.2012.2194716

29. Nouguier, F., C.-A. Gurin, and G. Soriano, "Analytical techniques for the Doppler signature of sea surfaces in the microwave regime-II: Nonlinear surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 49, No. 12, 4920-4927, 2011.
doi:10.1109/TGRS.2011.2153207

30. Thompson, D., T. Elfouhaily, and R. Gasparovic, "Polarization dependence of GPS signals reflected from the ocean," Proc. IGARSS 2000, 2000.

31. Khenchaf, A., "Bistatic scattering and depolarization by randomly rough surfaces: Application to the natural rough surfaces in X-band," Waves in Random Media, Vol. 11, No. 2, 61-89, 2001.
doi:10.1088/0959-7174/11/2/301

32. Voronovich, A. G. and V. U. Zavorotny, "Full-polarization modeling of monostatic and bistatic radar scattering from a rough sea surface," IEEE Trans. Antennas Propag., Vol. 62, No. 3, 1362-1371, 2014.
doi:10.1109/TAP.2013.2295235

33. Toporkov, J. V. and G. S. Brown, "Numerical study of the extended Kirchhoff approach and the lowest order small slope approximation for scattering from ocean-like surfaces: Doppler analysis," IEEE Trans. Antennas Propag., Vol. 50, No. 4, 417-425, 2002.
doi:10.1109/TAP.2002.1003376

34. Awada, A., M. Y. Ayari, A. Khenchaf, and A. Coatanhay, "Bistatic scattering from an anisotropic sea surface: Numerical comparison between the first-order SSA and the TSM models," Waves in Random and Complex Media, Vol. 16, No. 3, 383-394, 2006.
doi:10.1080/17455030600844089

35. Elfouhaily, T., B. Chapron, K. Katsaros, and D. Vandemark, "A unified directional spectrum for long and short wind-driven waves," J. Geophys. Res., Vol. 102, No. C7, 15781-15796, 1997.
doi:10.1029/97JC00467

36. Voronovich, A. G., "Small-slope approximation for electromagnetic wave scattering at a rough interface of two dielectric half-spaces," Waves in Random and Complex Media, Vol. 4, No. 3, 337-367, 1994.
doi:10.1088/0959-7174/4/3/008

37. Voronovich, A. G., Wave Scattering from Rough Surfaces, 2nd Ed., Springer-Verlag, 1999.
doi:10.1007/978-3-642-59936-1

38. Nie, D., M. Zhang, and N. Li, "Investigation on microwave polarimetric scattering from two dimensional wind fetch- and water depth-limited nearshore sea surfaces," Progress In Electromagnetics Research, Vol. 145, 251-261, 2014.
doi:10.2528/PIER14022505

39. Tsang, L., J. A. Kong, K. H. Ding, and C. O. Ao, Scattering of Electromagnetic Waves: Numerical Simulations, Vol. 2, Wiley-Interscience, 2001.
doi:10.1002/0471224308

40. Voronovich, A. G. and V. U. Zavorotny, "Theoretical model for scattering of radar signals in Ku and C-bands from a rough sea surface with breaking waves," Waves in Random and Complex Media, Vol. 11, No. 3, 247-269, 2001.

Dr. Peng-Ju Yang

Dr. Rui Wu

Dr. Xincheng Ren

Dr. Yuqiang Zhang