Determining the Effective Range of Radar Horizontal Reflectivity-Rainfall Intensity Relationship

Abstract

This study evaluated the applicability of the reflectivity-rainfall (Z-R) relationship using horizontal reflectivity. We reviewed the derivation procedure of the Z-R relationship and transformed the equation to estimate the parameters of drop size distribution from the observational data. The parameters of drop size distribution were estimated for the paired data of horizontal reflectivity and rainfall rate observed at the Gwanaksan and Biseulsan radar stations by applying this equation. Subsequently, the representative values of these estimated parameters were used to derive the Z-R relationship. Finally, we evaluated the performance of the Z-R relationship for representing the observed horizontal reflectivity-rainfall intensity data. It was observed that the difference between the theoretical estimation and the observed data increases as the radar reflectivity decreases. Moreover, the results confirmed that the Z-R relationship based on the assumption of exponentially distributed drop size distribution may not be applicable for all reflectivity ranges.