Crosswind ocean radar backscatter and two‐scale scattering model at low grazing angles

Abstract

[1] A two-scale model of rough surface in a crosswind ocean radar illumination is considered. Model characteristics such as polarization and azimuthal dependence are illustrated through numerical calculations. Predictions of the model are compared with rare field measurements made in a crosswind environment. Measurements were obtained at a 2°grazing angle. These data, collected by X-and Ka-band (9.3 and 34.6 GHz) radars under crosswind during the 1995 Coastal Ocean Probing Experiment (COPE) off the Oregon Coast, indicate that the backscatter intensity of local ''seaspikes'' measured with horizontal transmit-and-receive polarization (HH) reaches or exceeds that measured with the vertical transmit-and-receive polarization (VV). We suggest that for low grazing angles and in a crosswind environment, a radar geometrical condition can occur where some HH-spikes can be dominated by vertically polarized scattered radiation due to cross tilt of a long wave, when its local slope becomes greater than 45°.INDEX TERMS: 6959 Radio Science: Radio oceanography; 6969 Radio Science: Remote sensing; 4506 Oceanography: Physical: Capillary waves; 4504 Oceanography: Physical: Air/sea interactions (0312); KEYWORDS: radio oceanography, remote sensing, electromagnetic theory, capillary waves, air/sea interactions Citation: Smirnov, A. V., I. M. Fuks, and K. A. Naugonykh, Crosswind ocean radar backscatter and two-scale scattering model at low grazing angles,

Full-Polarization Modeling of Monostatic and Bistatic Radar Scattering From a Rough Sea Surface

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“…While there is an abundant literature on C, Ku, and X-band radar backscattering from wind-generated water surface waves in tank or oceanic conditions, the use of radar millimeter wavelength range (Ka band) has been far less documented. We found it limited to a few studies performed in airborne [Masuko et al, 1986;Nekrasov and Hoogeboom, 2005;Tanelli et al, 2006;Walsh et al, 1998;Vandemark et al, 2004;Walsh et al, 2008;Fjortoft et al, 2014], coastal [Long, 2001;Dyer et al, 1974;Smirnov et al, 2003], and wind-wave tank [Giovanangeli et al, 1991;Keller et al, 1995;Gade et al, 1998;Plant et al, 1999Plant et al, , 2004Ermakov et al, 2010] conditions. These studies have unveiled the specificity of Ka-band radar return in terms of backscattering cross section as well as Doppler signature when compared to lower microwave bands.…”

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