MULTIPLE-SCATTERING EFFECTS ON THE TRANSMISSION AND REFLECTION OF MILLIMETER PULSE WAVES IN RAIN

Numerical solutions of the vector two‐frequency radiative transfer equation are obtained to investigate the effects of multiple scattering on pulse propagation in rain. Only the case of circularly polarized incident wave is treated. First, the shape and magnitude of transmitted incoherent pulses in co‐ and cross‐polarized channels are compared with those of the incident pulses, and the effect of multiple scattering on communication quality is discussed. Next, the shape and magnitude of the reflected pulses in the main polarization channel are compared with those calculated by the conventional radar equation, and the difference of the two results is examined. In backward scattering, the radar returns of spherical raindrops in the cross‐polarized channel given by the multiple scattering calculations are often comparable to those obtained by the first‐order calculations for Pruppacher‐Pitter‐shaped distorted raindrops. The multiple scattering effect on the polarimetric interpretation of cross‐polarized radar returns from distorted raindrops is discussed. Copyright 1990 by the American Geophysical Union.