This letter illustrates the effects that the regular pattern of the metallic unions of a four-panel radome had on the polarimetric variables [differential reflectivity $Z_{\text {dr}}$ , copolar differential phase $\phi _{\text {dp}}$ offset, and copolar correlation coefficient ( $\rho _{hv}$ )] as well as on the sun measurements of a mobile X-band weather radar. In particular, we focus on the analysis of the spatial distribution of the biases and the temporal variability of the sun measurements. We show that the metallic unions result in a nonnegligible sinusoidal-like spatial variability of the estimated biases (on the order of 7°–8° for $\phi _{\text {dp}}$ offset and 0.4–0.5 dB for $Z_{\text {dr}}$ bias), as well as a drop in $\rho _{hv}$ in rain and a large temporal variability in the power measured by sun scans. These effects are compared with the measurements collected without a radome and with the measurements collected with a seamless monoblock radome on the same radar system. It is shown that operating without radome, when possible, has a positive impact on the data quality, largely reducing the spatial variability of the biases and increasing the $\rho _{hv}$ in rain. Similar performances, without the inherent risks, can be obtained as well with a seamless radome. Nevertheless, regardless of the form of operation, we advocate for monitoring the data quality as accurately as possible if quantitative applications are desired.

中文翻译：

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天线罩特性对气象雷达极化矩和太阳测量的影响

这封信说明了四面板天线罩的金属结合的规则图案对偏振变量[差反射率]的影响。 $ Z _ {\ text {dr}} $ ，同相微分相 $ \ phi _ {\ text {dp}} $ 偏移和同极相关系数（ $ \ rho _ {hv} $ ）]以及移动X波段天气雷达的日照测量。特别是，我们专注于分析偏差的空间分布和太阳测量值的时间变异性。我们表明，金属结合导致估计偏倚的不可忽略的正弦状空间变异（对于7°-8°的量级， $ \ phi _ {\ text {dp}} $ 偏移和0.4–0.5 dB $ Z _ {\ text {dr}} $ 偏见），以及下降 $ \ rho _ {hv} $ 在雨中，太阳扫描测得的功率随时间变化很大。将这些效果与在没有雷达罩的情况下收集的测量结果以及在同一雷达系统上通过无缝整体式雷达罩收集的测量结果进行比较。结果表明，在没有天线罩的情况下进行操作可能会对数据质量产生积极影响，从而大大降低了偏差的空间变异性并增加了 $ \ rho _ {hv} $ 在雨中。使用无缝天线罩也可以获得类似的性能，而没有固有的风险。但是，无论采用何种形式的操作，如果需要定量应用，我们都提倡尽可能准确地监视数据质量。