Data Quality Analysis and Basic Application of S-band Dual Polarization Weather Radar

Since 2015, the first batch of domestic dual polarization radars have been upgraded and put into operation in Yangjiang, Meizhou, Shaoguan and Guangzhou. In the early stage of polarization radar operation, due to the limitation of technology level, the polarization parameters are not stable, so it is necessary to make a preliminary analysis of the polarization parameters before using data. In this paper, the correlations of reflectivity (ZH), Signal-to-noise ratio(SNR), correlation coefficient (CC), differential reflectivity (ZDR), specific differential phase shift rate (KDP) are quantitatively evaluated by statistics and analysis of a typical stratiform cloud precipitation process observed by dual polarization radar. The results show that: (1) The system ZDR bias by using light rain is stable at about 0.1dB, which meets the accuracy requirements of ZDR (0.1-0.2dB) (2) When SNR <; 35, CC and ZDR values are disordered and untrustworthy. With the increase of SNR, the standard deviation of ZDR and CC decreased, and the data quality improved significantly. (3)when ZH <; 40 dBZ, the overall distribution of ZDR tends to be stable, mainly concentrates around the value of 0; when ZH >40 dBZ, ZDR and ZH have a positive correlation; (4) when ZH <; 40 dBZ, KDP is concentrated near 0; When ZH >40 dBZ, KDP has a strong sensitivity, and its growth rate is faster, which shows that KDP can better reflect the characteristics of heavy rainfall. Finally, three typical processes are analyzed according to the above characteristics. Compared with traditional weather radar, dual polarization radar:(1) It is more intuitive and accurate to recognize the echo type with dual polarization radar; (2) it can directly and effectively judge the hail area in the cloud; (3)The corresponding relationship between KDP and rainstorm warning level can be established. These preliminary analysis and results can better reflect the detection performance advantage and data quality of polarization radar, and have certain reference significance for the application of S-band dual polarization radar data.