双线偏振天气雷达是当前一种比较先进的天气雷达,它能同时获取云和降水特性的参量包括强度(Zh)、速度(V)、谱宽(W)、差反射率(Zdr)、差传输相移(Φdp)、比相差(Kdp)和相关系数(ρhv)。这些参量的数据精度决定了识别云和降水粒子及遥测区域降雨量的准确性。这些数据精度与回波信号的信噪比密切相关,当信噪比低于20 dB时(不同雷达有差异),偏振数据的精度明显变差;同时也与雷达的空间分辨率有关,当距离雷达较远时,由于雷达波束的展宽,其回波功率包含不同的水成物粒子的信号,这些都会带来数据精度的误差,影响偏振天气雷达的正确应用。另外,由于受到雷达发射功率的限制,在保证探测数据精度(也就是信号强度要满足信噪比的要求)的前提下,偏振数据的探测距离远低于强度信号的探测距离。为了保证回波信号有足够的信噪比和合适的空间分辨率,双偏振天气雷达的探测范围必须被控制在一个有效的范围内。本文结合偏振雷达探测数据的分析,从保证偏振天气雷达偏振参量数据精度的要求出发,研究探讨了我国现有的不同偏振天气雷达的有效探测范围,其结果对偏振雷达的设计生产和应用有重要的参考作用。
Dual-linear polarization radar as a special weather radar is followed with interest by people day by day.Some polarization parameters can been detected at same time such as Zh,V,W,Zdr,Φdp,Kdp and ρhv of cloud.The accuracy of polarization data controls the accuracy for rain rate estimating and hydrometeor classification.The precision of polarimetric parameters concern with the signal-noise ratio(S/N).When S/N under 20 dB,the accuracy of polarization data was deteriorated.The precision of data also concern with spatial resolution of radar,the echo signal mix with different hydrometeor signal because of the beam width when the cloud far away from radar.As transmitted power restrictions,the detection range of polarimetric parameters far below the radar reflectivity factor.To ensure that radar echo data has enough signal-noise ratio,the detection range must been controlled in a valid range.In this study,based on the polarization radar data analysis,think about the accuracy of polarization data,we discussed different wavelengths polarization radar's valid detection range,and it is of great use of for radar design and apply.
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