Attenuation of Microwaves through Rain for Various Drop-size Distributions

[摘要]  The attenuation of microwaves by rain at 3.2, 5- 7 and 10 cm wavelengths are computed. By using Laws and Parsons’ drop-size distributions, respective formulae for the three wavelengths, 0. 007R1.3, 0.0013R1.1 and 0.0003R, are obtained. Calculations based on drop-size data obtained by the M. R. I. group show that the attenuation at 3.2 cm for a given rainfall rate R is largely dependent on radar reflectivity Z for R>1 mm/hr. On the contrary, the attenuation at 5.7 cm depends only upon R approximately. For radar rainfall measurements, 5.7 cm wavelength is considered to be more appropriate than 3.2 cm.

[学科分类] 大气科学