Abstract The problem of optimum solar proxy is important for long-term and/or climatological studies of ionospheric parameters. Here we focus on possibly different optimum solar proxies for different ionospheric parameters, as they are affected by partly different spectral ranges of solar ionizing radiation. We use yearly average values of foF2 and foE of four European stations with long (1976–2014) and high-quality data (Juliusruh, Pruhonice, Rome, Slough/Chilton), and the global total electron content (G-TEC). Four solar proxies are used: F10.7, Mg II, solar Lymna-alpha flux Fα and sunspot numbers. The most important finding is that the optimum solar proxies are different for different ionospheric parameters. The most suitable solar proxy for foF2 is found to be Mg II, whereas for foE F10.7 evidently outperforms Mg II. Fα and sunspot numbers perform slightly worse but none of four solar proxies performs poorly. F10.7 is favored for G-TEC, to some extent surprisingly, as previous results favored rather Mg II.

中文翻译：

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长期电离层调查的最佳太阳代理是什么？

摘要 最佳太阳代理问题对于电离层参数的长期和/或气候学研究很重要。在这里，我们关注不同电离层参数可能不同的最佳太阳代理，因为它们受到部分不同的太阳电离辐射光谱范围的影响。我们使用四个欧洲站的 foF2 和 foE 的年平均值，这些站具有长期（1976-2014）和高质量数据（Juliusruh、Pruhonice、Rome、Slough/Chilton）和全球总电子含量（G-TEC）。使用了四种太阳代理：F10.7、Mg II、太阳 Lymna-alpha 通量 Fα 和太阳黑子数。最重要的发现是对于不同的电离层参数，最佳的太阳代理是不同的。发现最适合 foF2 的太阳能代理是 Mg II，而对于 foE F10.7 显然优于 Mg II。Fα 和太阳黑子数的表现稍差，但四个太阳代理中没有一个表现不佳。F10.7 有利于 G-TEC，在某种程度上令人惊讶，因为先前的结果有利于 Mg II。