Application Study Of Mobile C-Band Dual-Polarization Radar Quality Control And QPE Using Raindrop Size Distribution

Based on T-Matrix scattering simulation, The relationship between polarimetric radar measurements, attenuation coefficients, raindrop DSD of Jianghuai area was fitted. The main parameters which had influence on radar data was analyzed and basic quality control was conducted. By using a iterative range filtering technology on Φp,the KDP was obtained. Combining the Jianghuai area raindrop spectrum scattering simulation results, attenuation correction of ZH, ZDR were conducted by using the MKDP method.In addition, according to the characteristics of mobile dual polarization radar, the influence of short distance blockage on different dual-polarized parameters are analyzed. Finally, the DSD characteristics of a Jianghuai meiyu-front in July,2013 was analyzed and four QPE methods(R(Z), R(KDp), R(ZDR,ZH), R(ZDR,KDP)) and Error analysis were discussed,The main contents and conclusions are as follows:(1)Parameters of mobile C-band dual-polarization radar are inverted based on T-Matrix scattering simulation using raindrop size distribution. The parameters obtained through simulation have a high correlation between each other. u-Acurve was obtained by using simulation results, and Gamma distribution of raindrop DSD simulation was obtained by using polarimetric radar parameters.(2) In the process of basic quality control, number of samples M,SNR and correlation coefficient pHV are significant elements which influence the quality of radar polarimetric paraments.The results showed that radar polarimetric paraments is creditable when SNR is larger than 20dB.Systemic error of ZDR in scope of 20-34dB will increase with SNR. ZDR system error had no obvious change during the observation, but ZDR need to be calibrated when position removal and system malfunction occur.(3) It is good to use iterative range filtering technology on ΦDP.Finally using least squares method to calculate KDP can get satisfactory results.(4) ZH, ZDR were attenuation corrected using MKDP method based on raindrop classification which was on the basis of different DSD and attenuation coefficients fitted using raindrop size distribution.. Analysis of different correction methods and correction results by comparison with s-band radar showed that the MKDP method effect is obvious.(5)According to the characteristics of mobile radar, the influence of short distance blockage on different dual-polarized parameters were analyzed. The attenuation of reflectivity factor ZH was always in proportion to the degree of blockage, while ZDR and ΦDP will increase when encounter the cuspate blockage.KDP and pHV were always immune to the partial blockage.(6)Simulation coefficient of four QPE methods (R(Z), R(KDP),R(ZDR,ZH), R(ZDR,KDP)) were obtained by scattering simulation of raindrop size distribution. The DSD characteristics of a jianghuai meiyu-front in July,2013 were analyzed and error analysis were discussed. The results showed that drop spectrum structure was stable, the effect of various methods correction were similar. Rainfall error of using minutes data of rain gauge and radar rainfall estimate results can be reduced when using hours data compared with precipitation estimation results.