RAINFALL RATE MEASUREMENT WITH A POLARIMETRIC RADAR AT AN ATTENUATED WAVELENGTH

Among the many ways investigated for radar estimation of rainfall, pol arimetric methods are the most promising. However most polarimetric al gorithms are degraded by attenuation by precipitation and clouds and b y calibration error. A new method was recently proposed in which the d ifferential polarimetric attenuation is used to perform an accurate ra in rate measurement. The method is independent of the radar calibratio n and of the attenuation by undetected clouds. This algorithm is also usable as a qualitative hail detector, as well as a detector of anomal ous propagation. The goal of the paper is to describe the results of t he first experimental implementation of this method using the 35 GHz R ARELAIS radar, as attenuated radar, and the 3 GHz CAMRa radar as a ref erence. We show that the proposed algorithm is stable and enables us t o retrieve the actual rain rate even from an observed signal attenuate d by more than 30 dB. The results are insensitive to the value used fo r the power coefficient of the Z(R) relation.