An empirical method to improve rainfall estimation of dual polarization radar using ground measurements

Abstract

Abstract. This study presents an easy and convenient empirical method to optimize polarimetric variables and produce more accurate dual polarization radar rainfall estimation. Weather Radar Center (WRC) in Korea Meteorological Administration (KMA) suggested relations between polarimetric variables (Z -Z DR and Z -K DP ) based on a 2-D Video Distrometer (2DVD) measurements in 2014. Observed polarimetric variables from CAPPI (Constant Altitude Plan Position Indicator) images 10 composed at 1.5 km of height were adjusted using the WRC"s relations. Then dual polarization radar rainfalls were estimated by six different radar rainfall estimation algorithms, which are using either Z, Z and Z DR , or Z, Z DR and K DP . Accuracy of radar rainfall estimations derived by the six algorithms using the adjusted variables was assessed through comparison with raingauge observations. As a result, the accuracy of the radar rainfall estimation using adjusted polarimetric variables has improved from 50 % to 70 % approximately. Three high rainfall events with more than 40 mm of maximum hourly rainfall 15 were shown the best accuracy on the rainfall estimation derived by using Z, Z DR and K DP . Meanwhile stratiform event was gained better radar rainfalls estimated by algorithms using Z and Z DR .