The study of the influence of the surface waves formation conditions and rain on the acoustic waves backscattering by the water surface applied to remote sensing of the sea surface

The study addresses to the problem of ground calibration and verification of satellite measurements of the surface waves characteristics. For measurements we propose to use the Doppler underwater acoustic wave gauge of a special design, which can directly measure the sea wave statistical characteristics that effect on the electromagnetic wave backscatter of the same wavelength. The main features of the acoustic wave gauge are the use of Doppler ultrasound sonar and antennas with different antenna patterns. In the experiment, measurements are carried out by sonar submerged to the bottom and antennas oriented vertically upwards. Retrieval algorithms are based on the dependence of the Doppler spectrum of the reflected acoustic signal from the water surface statistical characteristics. This method allow to measure all second-order statistical parameters of sea waves, namely, the variance of the vertical orbital velocity component, the variance of slopes in two mutually perpendicular directions, and the cross-correlation coefficients of slopes and the vertical orbital velocity component. Currently, especially important is the possibility of measuring the variance of slopes of the water surface, the same as measured by radar systems.