Study of a Microwave Radar Signal Backscattered at Small Incidence Angles: In-Situ Measurements

We present the results of data processing of the field experiment devoted to a study of a microwave signal backscattered by a rough water surface and compare them with the theoretical estimates. The measurements were conducted sequentially using a radar with parabolic and knife-beam antennas. The radar was mounted on the Molitovsky bridge at a height of 40 m across the Oka river in Nizhny Novgorod, Russia. For the radar with knife-shaped antenna pattern, we examined the reflected-signal power and the shift and width of the Doppler spectrum as functions of the azimuthal angle for the nadir sounding. For the parabolic antenna, we studied the reflected-signal power as a function of the incidence angle. Comparison with the experimental data shows that the developed theoretical model of a Doppler spectrum is in good agreement with the observations. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 8, pp. 661–673, August 2005.     

Doppler Spectra of Centimeter and Millimeter Microwaves Backscattered from a Rough Water Surface at low Grazing Angles

We present the results of processing of X- and Ka-band radar signals backscattered from a rough water surface at low grazing angles. Processing is made by the method of decomposing a Doppler spectrum into three basic line profiles. Each of these profiles corresponds to a certain scattering mechanism. Comparative evaluations of the contribution of the Bragg mechanism described by the Gaussian line profile and two non-Bragg mechanisms described by the Lorentz and Voigt profiles are obtained.