Behavior of non-Rayleigh statistics of microwave forward scatter from a random water surface

Measurements of the phase-quadrature components of the microwave field forward-scattered from random water waves have continued since the observance in 1963 of non-Rayleigh probability distributions of the incoherent scattered field. Measurements of the variances of the phase-quadrature components of the incoherent field at various phase angles with respect to the coherent field have yielded new results not explained by plane-wave theory: 1) The equiprobability ellipse of the phase-quadrature components of the incoherent field rotates us a function of apparent surface roughness. 2) The rotation of the equiprobability ellipse varies more rapidly with roughness for "narrow" surface illumination and less rapidly for "broad" illumination. 3) The greatest ratio of the two variances appears to rise from unity with increasing roughness to a peak value (maximum departure from Rayleigh), and presumably decreases at greater roughnesses. The data indicate that nonplanar illuminating and receiving wavefronts may be responsible for these divergences from plane-wave theory.