Comparison of Quantitative Precipitation Estimation in Northern Taiwan Using S- and C-band Dual-polarimetric Radars

The operational radar network in Taiwan will be composed with dual-polarimetric radars at S and C-band to monitor extreme precipitation. Various polarimetric parameters of different wavelength radars have distinct advantages and disadvantages in terms of quantitative precipitation estimation (QPE). Four different QPE relationships, namely R(Z), R(K_DP), R(Z, Z_DR) and R(K_DP,Z_DR), of each rain types are obtained from 2D-Video disdrometer data and applied to the heavy rainfall events observed by both RCWF S-band and NCU C-Pol dual-polarimetric radars from 2014 to 2015. The goal of this study is to investigate the performances of radar-based QPE from different wavelengths at the same area. The results indicate that (1) the results show that the QPE are improved after applied the coefficients of corresponding precipitation-type (Spring, Mei-Yu, Summer Convection, Winter and Typhoon). (2) Both of the attenuation correction by PHI_DP–based algorithm and wet radome correction by self-consistency method greatly improve the QPE from RCWF and NCU C-Pol radars. (3) The QPE from K_DP-based relationships which combine with R(Z) are most accurate than Z-based relationships. When two radars have comparable sampling data numbers, NCU C-Pol radar shows the advantage of K_DP parameter for QPE at shorter wavelength with lower relative root mean square error, normalized mean bias and higher correlation coefficient.