Laboratory study of cross-polarized radar return under gale-force wind conditions

This paper presents data of laboratory experiments on a high-speed wind-wave flume of the Institute of Applied Physics Nizhny Novgorod, Russian Federation, which are devoted to the investigation of the X-band co-polarized and de-polarized radar return in a wide range of high wind speeds from 8 to 40 m s–1. Microwave measurements were accompanied by the measurements of airflow and wave field parameters. Experiments showed that alternatively to the co-polarized return, the dependency of the de-polarized return on the wind speed does not saturate, although the growth rate decreases at wind speed exceeding 30 m s–1. Comparison 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.