High-frequency diffraction corrections to backscattering cross sections from a rough three-dimensional surface.
Diffraction corrections to scalar wave fields at perfectly free and rigid rough surfaces were derived by two iterations of the corresponding integral equations. These diffraction corrections to the pressure or normal velocity (which, in the geometrical optics limit, are doubled at perfectly rigid and free surfaces, respectively) were obtained with an accuracy of approximately 1k(2), where k is the wave number of incidence radiation. Based on these corrections to the surface fields, the backscattering cross sections at normal incidence from the statistically rough Gaussian surfaces were derived. It was found that for the gentle roughness, diffraction results in effective "smoothing" of roughness for rigid and free surfaces and increasing of the backscattering cross sections, but for a rigid surface with steep roughness, the "fictitious" surface can be more rough than the real one, and the diffraction corrections become negative.
Fuks
Iosif
I
Zel Technologies, LLC and NOAA/Earth System Research Laboratory, 325 Broadway, R/PSD-99, Boulder, Colorado 80305, USA. iosif.fuks@noaa.gov
D000162:Acoustics; D007700:Kinetics; D008962:Models, Theoretical; D016011:Normal Distribution; D011827:Radiation; D012542:Scattering, Radiation; D013499:Surface Properties