Propagation through rain
Abstract
Both the attenuation due to rain and the effectiveness of circular polarization in reducing rain clutter depend upon the transmission properties of the rain medium. Both the rainfall rate and specific attenuation were computed for each measured drop size distribution, assuming that: rain drops are homogeneous water spheres; raindrops of a given size are uniformly distributed in space in accordance with a Poisson process; single scattering theory may be used to sum the scattered field from each rain drop; and the rain drop size distributions that may occur along a radar path are identical to those observed at the surface. Calculations show that the maximum possible variation in attenuation for a given rain rate is by a factor of more than 20. Estimates show that the cross polarization increases with frequency for frequencies less than 20 GHz and may significantly decrease the CDR (circular depolarization) for the system if large distances are traversed. The results quoted indicate that attenuation and cross polarization may be important to radar system design.
 Publication:

NEREM 74; Northeast Electronics Research and Engineering Meeting
 Pub Date:
 1974
 Bibcode:
 1974ieee.meet..135C
 Keywords:

 Atmospheric Attenuation;
 Circular Polarization;
 Microwave Scattering;
 Microwave Transmission;
 Radar Transmission;
 Rain;
 Depolarization;
 Microwave Attenuation;
 Phase Shift;
 Raindrops;
 Regression Analysis;
 Superhigh Frequencies;
 Communications and Radar