On a Problem of Marine Current Velocity Estimation from Microwave Radar Data

Abstract

The paper is devoted to the problem of estimating marine current velocity from microwave radar data, one of the important tasks of sea remote sensing. We present some results of simultaneous measurements of radar scatterers velocities and sea current and wind velocities. Radar scatterers velocities were measured using a dual-polarized (VV/HH) Doppler radar operating in S/C/X bands. The experiments were carried out in the coastal zone of the Black Sea at moderate incidence angles (30–70 degrees). It was obtained that the subsurface current velocity (current in the upper layer of ten centimeters) retrieved from the Bragg component of the radar return can be used to estimate changes in marine current (a part of the sea current that is not related to the wind) at constant wind speed. The subsurface current velocity is found as a vector sum of the current velocity measured at a depth of 1 m and the wind component equal to 1–3% of the wind speed. Possibilities of estimating the current velocity from VV/HH/PD data are analyzed.