Technique for calibration of meteorological radars using differential phase

Abstract

Meteorological radars that are capable of making both polarisation diversity and phase measurements require an accurate method for absolute power calibration to achieve their full potential. A technique is described which uses a combination of differential reflectivity and differential phase measurements in rain to achieve this. The method is demonstrated using data obtained with the 3 GHz Chilbolton radar, which was recently upgraded to measure differential phase and Doppler velocity. The sensitivity of this technique to the assumed drop size distribution is estimated, and shown to have a minor effect on the accuracy of the calibration.