Extracting Rainfall Rates from X-band CDR Radar Data by Using Differential Propagation Phase Shift

Abstract

In this paper, the method of using differential propagation phase shift ?Φ to measure rain rate R from X-band circular depolarization ratio (CDR) radar data is presented. The principle of this method is based on the fact that there is a relationship between ?Φ and R. The relationship between ?Φ and R is investigated under various parameters such as water temperature, raindrop shape, and drop-size distribution form. Differential backscattering phase shift ?δHV is related to ?Φ, and this makes it possible to extract ?Φ from CDR radar data and thus to estimate rain rates. The ?cleaning? procedures are utilized to minimize the effects of canting angle. Limitations due to noise and quantization in using ?Φ to measure R are discussed. Rain-rate measurements obtained by raingage and by radar agree well.