Laboratory modelling of cross-polarized radar return at severe wind conditions

Laboratory experiments directed to investigation of co-polarized and de-polarized X-band microwave radar return from the water surface at strong and hurricane wind were carried out in the high-speed wind-wave flume. Microwave measurements were accompanied by the measurements of air-flow and wave field parameters. Experiments showed that alternatively to the co-polarized return, the dependency of the de-polarized return on the wind speed do not saturate, although the growth rate decreases at wind speed exceeding 30 m/s. Comparison of the of the experimental data with the composite-surface Bragg scattering model for the measured parameters of the wind and waves showed, that the model is in agreement with measurements of microwave co-polarized return, but fails to describe the de-polarized radar return. The obtained dependency of de-polarized radar return was compared with the empirical geophysical model function based on collocated airborne and satellite data.