Performance of Dual-Polarization X-band Radar Network Quantitative Precipitation Estimation during Super Typhoon Hato

The Foshan Meteorological Service radar network consists of four high spatiotemporal resolution dual-polarization X-band radars with the aim to monitor sever weather events. Compared with conventional single-polarization radar, the dual-polarization radar can acquire more polarization parameters such as Z_dr, Φ_dp, K_dp and ρ_hv. These parameters have numerous advantages for radar precipitation identification and quantification. With this high spatiotemporal continuous radar data, users can issue more precise severe weather watches and warnings to reduce losses of life and property. This study evaluates the performance of rainfall data from three normally operating radars of this radar network during super Typhoon Hato which landed in Zhuhai on Aug. 23, 2017 and caused 24 deaths and a significant economic loss of $6.82 billion. Considering that the polarization parameter K_dp is less sensitive to precipitation attenuation, partial beam blockage and the radar absolute calibration error, the relation between rain rate R and K_dp, i.e. R (K_dp), is used to estimate typhoon precipitation with validation from ground rain gauge observations. These statistical characters such as relative bias (RB), root-mean-squared error (RMSE), correlation coefficient (CC), probability of detection (POD), false alarm ratio (FAR) and critical success index (CSI) are proposed as evaluation criteria. The fused K_dp fields and merged rainfall maps are presented in this work.

Keywords: X-band; dual-polarization radar; QPE; Typhoon Hato