Measurement of the variance of water surface slopes by a radar: Verification of algorithms

A full-scale experiment is carried out to study backscattering of a microwave radar signal by a rough water surface during flight over the Gorky water storage. A centimeter-wavelength Doppler radar with a knife-beam antenna oriented vertically downward was installed on the helicopter. The main goal of the experiment was a functional test of the modified radar system and new retrieval algorithms of the variance of surface slopes of a rough water surface and direction of the wind-wave propagation. The data analysis confirmed that the reflected power and the Doppler spectrum width depend on the direction of the wind-wave propagation. Two new algorithms were used for retrieval of the surface-slope variance. The processing of data showed that these algorithms make it possible to determine the variance of the scattering-surface slopes from a moving carrier without bounds on the flying height (such a capability was absent earlier). The direction of the wind-wave propagation is unambiguously determined by the Doppler spectrum width. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 5, pp. 399–412, May 2008.