Radar backscattering from Gerstner's sea surface wave

Abstract In the framework of a two-scale scattering model, radar backscattering from the rough sea surface was considered. The sea surface was modelled as a superposition of a nonlinear, large-scale Gerstner's wave and small-scale resonant Bragg scattering ripples. The zero-order diffracted field was found by a geometrical optics approach, with shadowing taken into account, and by an ‘exact’ solution of the diffraction problem obtained numerically. For vertical and horizontal polarizations, the spatial distribution of specific scattering cross sections along the large-scale wave was obtained. The spatially averaged specific backscattering cross sections, as well as the mean Doppler frequency shifts at both polarizations, obtained by the geometrical optics approach are compared with those obtained by using the ‘exact’ solution of the large-scale diffraction problem. The roles of shadowing and multiple wave scattering processes are discussed, and qualitative explanations of the difference between these two approaches are given.

[1]  Jakov V. Toporkov,et al.  Numerical simulations of scattering from time-varying, randomly rough surfaces , 2000, IEEE Trans. Geosci. Remote. Sens..

[2]  Valery U. Zavorotny,et al.  The effect of steep sea-waves on polarization ratio at low grazing angles , 2000, IEEE Trans. Geosci. Remote. Sens..

[3]  Multiple radio wave scattering by sea surface at low grazing angles , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[4]  F. Bass,et al.  Wave scattering from statistically rough surfaces , 1979 .

[5]  S G Hanson,et al.  Polarization dependency of enhanced multipath radar backscattering from an ocean-like surface , 1995 .

[6]  I. M. Fuks.  Theory of radio wave scattering at a rough sea surface , 1966 .

[7]  V. I. Tatarskii,et al.  Behaviour of scattering from a rough surface at small grazing angles , 1999 .

[8]  Dennis B. Trizna,et al.  A model for Brewster angle damping and multipath effects on the microwave radar sea echo at low grazing angles , 1997, IEEE Trans. Geosci. Remote. Sens..

[9]  I. M. Fuks,et al.  Emissivity of a statistically rough surface including multiple reflections , 1993 .

[10]  Alexander G. Voronovich,et al.  Wave diffraction by a concave statistically rough surface , 1999 .

[11]  Donald E. Barrick,et al.  First-order theory and analysis of MF/HF/VHF scatter from the sea , 1972 .

[12]  D. Barrick,et al.  On the Nonlinear Theory for Gravity Waves on the Ocean's Surface. Part I: Derivations , 1977 .

[13]  G. Valenzuela.  Theories for the interaction of electromagnetic and oceanic waves — A review , 1978 .

[14]  G. Valenzuela,et al.  Study of Doppler spectra of radar sea echo , 1970 .

[15]  D. E. Barrick,et al.  On the nonlinear theory for gravity waves on the ocean's surface. Part II : Interpretation and applications , 1977 .

[16]  I. Ostrovsky,et al.  Very High Frequency Radiowave Scattering by a Disturbed Sea Surface , 1968 .

[17]  I. Ostrovsky,et al.  Very high frequency radiowave scattering by a disturbed sea surface Part I: Scattering from a slightly disturbed boundary , 1968 .