Microwave backscatter from non-Gaussian seas

Rough-surface scattering theory is applied to study microwave backscattering from seas characterized by a non-Gaussian wave-height distribution. The relationship of the geometrical optics limit of rough-surface scattering theory to the probability density of surface slopes is used to relate the coefficients of Gram-Charlier expansions, describing measured slope statistics, to the wavenumber spectra of non-Gaussian surface components. Functional forms for the spectra consistent with measured slope statistics are assumed, and the backscatter predicted by rough-surface scattering theory is compared with measured cross sections. The predicted upwind-downwind asymmetry of scattering cross sections is comparable to that observed, and a measurable dependence of cross sections on atmospheric stability is predicted.

[1]  Ezekiel Bahar,et al.  Scattering cross sections for random rough surfaces: Full wave analysis , 1981 .

[2]  W. L. Jones,et al.  Aircraft measurements of the microwave scattering signature of the ocean , 1977 .

[3]  Bruno O. Shubert,et al.  Random variables and stochastic processes , 1979 .

[4]  O. Phillips.  The dynamics of the upper ocean , 1966 .

[5]  D. E. Barrick,et al.  Relationship between slope probability density function and the physical optics integral in rough surface scattering , 1968 .

[6]  W. Plant.  A two-scale model of short wind-generated waves and scatterometry , 1986 .

[7]  J H Churnside,et al.  Scanning-laser glint measurements of sea-surface slope statistics. , 1997, Applied optics.

[8]  K. Katsaros,et al.  A Unified Directional Spectrum for Long and Short Wind-Driven Waves , 1997 .

[9]  Robert E. McIntosh,et al.  Revised ocean backscatter models at C and Ku band under high-wind conditions , 1999 .

[10]  C. Cox.  Statistics of the sea surface derived from sun glitter , 1954 .

[11]  O. I. Yordanov,et al.  Non‐Gaussian effects in the two‐scale model for rough surface scattering , 1992 .

[12]  Abderrahim Bentamy,et al.  Ocean surface wind fields estimated from satellite active and passive microwave instruments , 1999, IEEE Trans. Geosci. Remote. Sens..

[13]  Suzanne T. McDaniel.  Small-slope predictions of microwave backscatter from the sea surface , 2001 .

[14]  Werner Alpers,et al.  Airborne measurements of the ocean radar cross section at 5.3 GHz as a function of wind speed , 1986 .

[15]  Athanasios Papoulis,et al.  Probability, Random Variables and Stochastic Processes , 1965 .

[16]  Stuart D. Smith.  Coefficients for sea surface wind stress, heat flux, and wind profiles as a function of wind speed and temperature , 1988 .

[17]  Suzanne T. McDaniel.  Microwave backscatter from directional seas , 2002 .

[18]  Frank J. Wentz,et al.  A model function for the ocean‐normalized radar cross section at 14 GHz derived from NSCAT observations , 1999 .

[19]  M. Donelan,et al.  Radar scattering and equilibrium ranges in wind‐generated waves with application to scatterometry , 1987 .

[20]  Fuk K. Li,et al.  Measurements of Ocean Surface Stress Using Aircraft Scatterometers , 1997 .

[21]  F. J. Wentz,et al.  A model function for ocean radar cross sections at 14.6 GHz , 1984 .

[22]  C. Cox.  Slopes of the sea surface deduced from photographs of sun glitter , 1956 .

[23]  David L. T. Anderson,et al.  Scatterometer data interpretation: Estimation and validation of the transfer function CMOD4 , 1997 .

[24]  Fuk K. Li,et al.  Observations of radar backscatter at Ku and C bands in the presence of large waves during the Surface Wave Dynamics Experiment , 1995, IEEE Trans. Geosci. Remote. Sens..