TILT MODULATION OF HIGH-RESOLUTION RADAR BACKSCATTER CROSS-SECTIONS -UNIFIED FULL-WAVE APPROACH

The unified full wave approach is used to determine the tilt modulatio n of the like and cross polarized (high resolution) radar backscatter cross sections for the rough sea surface. Thus, real or synthetic aper ture radars (SAR) with small effective footprints (resolution cells) a re considered here. Since the unified full wave approach accounts for Bragg scattering as well as specular point scattering in a self-consis tent manner, it is not necessary to adopt a two-scale model for the ro ugh sea surface. The sea surface slope probability density functions i s assumed to be Gaussian in this work. The backscattering cross sectio ns are evaluated for all angles of incidence (normal to grazing). For tilts in the plane of incidence, the modulation of all the cross secti ons is largest at angles of incidence THETA0' = 10-degrees. The cross- section modulation due to tilts perpendicular to the plane of incidenc e critically depends upon the incident and scattered polarizations. Th e effective filtering of the large scale spectral components of the ro ugh sea surface by the high resolution radar is accounted for and the dependence of the cross section tilt modulation upon the size of the e ffective footprint is determined.