Iterative Correction for Attenuation of 5 cm Radar in Rain

Abstract

The attenuation of 5 cm radar in rain is investigated theoretically for stratiform and thunderstorm drop size distributions. An iterative attenuation estimation scheme is presented. The effects of attenuation on radar precipitation measurements and the capabilities of the attenuation estimation technique are considered for a variety of hypothetical storm sizes and errors in radar calibration, assumed temperature and assumed drop size distribution. This study indicates that 5 cm radar is an adequate precipitation measuring radar for storms under about 50 dBZ, and that if calibrated correctly and used with the iterative attenuation correction scheme, the 5 cm radar can function moderately well up to about 60 dBZ. Radar calibration accuracy is seen to be a limiting criterion for attenuation correction. The results of this study point out the need for raingages in most situations requiring accurate rainfall measurement.