Study of the Doppler Spectrum of the Microwave Radar Signal Backscattered from the Water Surface at Low Incidence Angles in the Presence of a Constant Current: Experiment and Modeling

Measurements of the water surface backscatter at low incidence angles were performed using a Ka-band Doppler radar from the bridge over the Oka river in Nizhny Novgorod in June-October of 2019. Incidence angles varied from nadir to 25° during experiments. In this paper the first results of experimental data processing are presented and the dependency of Doppler frequency shift on incidence angle and an azimuth angle are analyzed. Data acquired in the experiments can be used for validation of theoretical models. The method for the estimation of the velocity of surface current using Doppler central frequency shift is introduced and validated.