Determination of the Significant Wave Height from Doppler Radar Images of the Sea Surface

This paper theoretically and experimentally considers the problem of determining the significant wind wave height based on coherent radar sounding of the sea surface. It is shown that the modulation of the velocity of radio wave scatterers by the orbital velocities of energy-carrying waves makes it possible to find an unambiguous relationship between the Doppler velocities measured with a coherent radar and the significant wave height. The problem of the influence of shading of sea surface areas by wave crests during sounding at small grazing angles is studied depending on the radar installation height and the significant wave height. The paper uses an original empirical model of the Doppler velocity of microwave radio wave scatterers on the sea surface, which demonstrates a good agreement with the experimental data. As a result, a remote sensing method for determining the significant wind wave height is proposed, which does not require calibration and is applicable from both fixed bases and moving carriers. The accuracy of the proposed remote sensing method is estimated based on experimental data obtained at a stationary oceanographic platform in the Black Sea in 2021. The correlation coefficient between the significant wave height according to contact and remote measurements was 0.9 at a root mean square error of 15 cm.