The possibility of rainfall estimation using R(Z,Z_DR,K_DP,A_H): A case study of heavy rainfall on 25 August 2014 in Korea

Abstract. To improve the accuracy of polarimetric rainfall relations for heavy rainfall, an extreme rainfall case was analysed and some methods were examined. The observed differential reflectivity (Z_DR) quality check was theoretically investigated using the relation between the standard deviation of differential reflectivity and cross correlation, and the light rain method for Z_DR bias was also applied to the rainfall estimation. The best performance for this heavy rainfall case was obtained when the moving average of Z_DR over a window size of 9 gates was applied to the rainfall estimation using horizontal reflectivity (Z_H) and Z_DR and to the calculation of Z_H bias. The differential reflectivity calculated by disdrometer data may be an alternative to the vertical pointing scan for calculating Z_DR bias. The accuracy of the combined rainfall relation, R(Z,Z_DR,K_DP,A_H) was relatively insensitive to Z_DR and Z_H biases in both observations and simulations.