The backscattering cross sections of snow particles and the radar reflectivity factor

The backscattering cross section and the radar reflectivity factor were analyzed in K-band. The backscattering cross section of a sphere was calculated from the first term of Mie formulas to the third one. In this band, it was possible to obtain the backscattering cross section with size less than 1.5cm from these terms. The radar reflectivity factor and spectrum were measured using a small K-band Doppler radar. The images of falling snow particles were simultaneously captured to measure size and falling velocity. Using area equivalent diameter of image data, the backscattering cross sections were calculated. The melted diameter of snow image was also computed for these cross sections. The radar reflectivity factor of the K-band radar was compared with the sum of backscattering cross sections using snow particle images.

1. INTRODUCTION

It is useful for weather radar to estimate precipitation rate from measurements of radar reflectivity factor [1], [2]. This radar reflectivity factor is calculated from the sum of the backscattering section of precipitation particle in the observation volume. The scattering properties of electromagnetic waves due to precipitations are important in meteorological radar measurement.