X波段双线偏振多普勒雷达资料质量评估

Evaluation on Data Quality of X-band Dual Linear Polarization Doppler Weather Radar

以山东省首部X波段全固态双线偏振多普勒天气雷达724XSP观测的几次降水过程资料为例,与济南站多普勒天气雷达（CINRAD/SA）资料进行对比分析,并利用XSP雷达观测的层状云降水资料进行偏振参量的质量分析。结果表明：XSP雷达波束在穿越层状云云体时的衰减比较均匀,与SA雷达探测的云体结构比较接近,但XSP雷达对45 dBZ以上强回波的探测能力较差,尤其探测冰雹云云体结构时二者差别较大。对偏振参量分析发现,当SNR〈10 dB时,ZDR、CC、ΦDP和KDP等偏振参量受噪声影响明显,误差较大不可信;当SNR位于15-23 dB时,ZDR和CC的测量值有明显波动,质量较差;XSP雷达的ZDR测量值较理论值偏低0.5 dB;ΦDP和KDP资料受衰减影响较小,当SNR〉10dB时,质量比较可靠。

Based on the observation data of X-band dual linear polarization Doppler weather radar（724XSP） in Liaocheng of Shandong Province for several precipitation processes,the data quality of polarization parameters from 724XSP radar for these stratiform cloud precipitation processes were evaluated. Combined with the reflectivity factor data of S-band Doppler radar（CINRAD / SA） in Ji＇nan,the ehco intensity between XSP and SA radars was contrasted. The results showed that the beam of XSP radar spreading in stratiform cloud was uniformly attenuated,the structure of stratiform cloud detected by XSP radar was similar to that by SA radar.However,the detecting ability of XSP to echo intensity above 45 dBZ was poor,especially the difference of hailstorm cloud structure between XSP and SA radars was great. The effects of nose on polarization parameters of XSP radar were significant when SNR（signal to nose ratio） was less than 10 dB,the error of polarization parameters was great. The value of ZDR and CC fluctuated greatly when SNR was from 15 dB to 23 dB,the quality of ZDR and CC data was bad. The monitored values of ZDR from XSP radar were lower 0.5 dB than theoretical values. The influences of beam attenuation on ΦDP and KDP were smaller,the quality was reliable especially when SNR exceeded 10 dB.