Abstract. Radio waves propagating in the atmosphere are affected by the prevailing atmospheric state. The state of the atmosphere can cause radio waves to refract more or less towards the ground. When the refractive index of the atmosphere differs from standard atmospheric conditions the propagation is called anomalous. Radars which are affected by anomalous propagation can receive ground clutter far beyond the radar horizon. In this work 4.5 years of data from five operational Swedish C-band dual polarization weather radars are presented. Analyses of the data reveal a strong seasonal cycle and weaker diurnal cycle in ground clutter from coastal regions across nearby waters. The impact of anomalous propagation on ground clutter, measured with horizontal and vertical polarization, was compared but no clear difference was found.

中文翻译：

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瑞典附近水域异常传播的观测

摘要。在大气中传播的无线电波会受到当时大气状态的影响。大气状态会导致无线电波或多或少地向地面折射。当大气的折射率不同于标准大气条件时，传播称为异常。受异常传播影响的雷达可以接收到远远超出雷达地平线的地面杂波。在这项工作中，展示了瑞典五台运行中的 C 波段双极化天气雷达 4.5 年的数据。对数据的分析表明，附近海域沿海地区的地面杂波具有很强的季节性循环和较弱的昼夜循环。比较了水平和垂直极化测量的异常传播对地面杂波的影响，但没有发现明显差异。