Statistical analysis of Real Aperture Radar field backscattered from sea surfaces under moderate winds by Monte-Carlo simulations
Résumé
The statistical properties of the electromagnetic field backscattered from sea surfaces are studied by using asymptotic numerical methods. Sea surfaces are modeled by using the Elfouhaily et al. spectrum model. The influence of the radar spatial resolution on the field statistics is studied for various wind conditions and radar configurations, by considering equal range and azimuth resolutions. It is observed that the backscattered field phase can be assimilated to a uniform distribution and that the amplitude resembles a Rayleigh distribution. Moreover, reducing the radar spatial resolution d induces a stronger variability of the backscattered field amplitude and a departure from the Rayleigh distribution. This departure is enhanced particularly when the radar look approaches the cross-wind direction and also when increasing the wind speed. Also, a fitting of the amplitude distribution with various theoretical statistical laws (gamma, Weibull, K, and so on) highlights the general good fitting of the K distribution, which is in agreement with previous work led from measurements.