双极化天气雷达的工作模式与极化隔离度

双极化天气雷达主要有两种工作模式,即同时发射同时接收模式和交替发射同时接收模式。比较了两种工作模式在谱参数估计精度、速度测量范围、地杂波抑制、信噪比等方面各自的优势和不足,并分析了天气雷达中的退极化现象及其对差分反射率产品的影响;以线性退极化比为例,讨论了极化参数的测量误差对双极化天气雷达系统极化隔离度的要求。理论分析和计算表明,精确的极化测量对双极化天气雷达的极化隔离度提出了非常严格的要求。

Operating Modes and Polarization Isolation Degree of Dual Polarization Weather Radar

Dual polarization weather radar mainly has two operating modes: simultaneous transmission and reception; horizontal/vertical alternate transmission and simultaneous reception. Comparison is conducted on the advantages and disadvantages of the two modes in aspects of the accuracy of spectral moment estimation, the measurement range for velocity, ground clutter suppression, signal to noise ratio, and so on, and the depolarization phenomenon in weather radar as well as its effect on differential reflectivity products are analyzed. Taking linear depolarization ratio as an example, the polarization isolation degree in dual polarization weather radar is discussed. Theoretical analysis and computation indicates that accurate polarimetric measurement demands a strict polarization isolation degree.