Experimental Measurements of the Doppler Spectrum of the Reflected Signal at Near-Nadir Probing: Backscattering From Ice and Water Surface

In the radar remote sensing of sea ice, the main informative parameter is the backscattering radar cross section (RCS), which does not always make it possible to unambiguously determine the kind of scattering surface (ice/sea waves) and therefore leads to errors in estimating the area of the ice cover. This paper continues a line of articles that explore the possibility of using the Doppler spectrum (DS) of the reflected signal at near-nadir probing for ocean remote sensing. Experimental DS of the microwave signal reflected from water surface and ice cover are compared. The experiment took place on the Nizhny Novgorod cable car. Pulsed X-band radar was installed on a technological trolley and performed measurements in two modes that worked sequentially while moving. In the Doppler mode the DS of the reflected signal was measured. It contains information about the statistical parameters of the surface. Data processing was carried out and the first results confirmed the assumption that the DS can be an effective tool for classifying the type of the underlying surface according to the «ice/water» criterion. Comparison with model of DS for sea ice has shown that the general behavior of the DS for ice and waves in experiment is in agreement with theory. A development of the theoretical description of the DS for freshwater ice and comparison with experimental data is planned for the future research.