Accession Number : ADP006184

Title :   The Effect of Oblate Spheroidal Drops on Rain Attenuation at 94 GHz: Comparison Between Theory and Experiment,

Corporate Author : FYSISCH EN ELEKTRONISCH LAB TNO THE HAGUE (NETHERLANDS)

Personal Author(s) : Keizer, W. P.

Report Date : SEP 1989

Pagination or Media Count : 10

Abstract : Rain induced attenuations for horizontally and vertically polarized waves at 94 GHz have been measured on a 935m link and compared with theoretical predictions. During the experiment which covered a period of two years also the raindrop size distribution along the propagation path was recorded. The theoretical predictions were based on the actually measured raindrop size distributions and assumed both spherical and spheroidal shapes for the raindrops. The calculations for oblate spheroidal raindrops showed that horizontally polarized waves are more attenuated by rain than vertically polarized waves. It was also found that the Mie scattering theory for spherical raindrops underestimates the rain attenuation for both polarizations. The comparison of the measured rain attenuation results with the predictions confirmed completely the outcome of the theoretical calculations. A remarkable improvement in the accuracy of rain attenuation modelling for horizontal and vertical polarization was noted when a spheroidal drop shape was taken into account instead of the spherical shape.

Descriptors :   *RAINDROPS, *ATMOSPHERIC ATTENUATION, SHAPE, MIE SCATTERING.

Subject Categories : Meteorology
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE