Is the F10.7cm – Sunspot Number relation linear and stable?
Is the F10.7cm – Sunspot Number relation linear and stable?
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F10.7cm - 太阳黑子数关系是线性且稳定的吗？
DOI：
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发表时间：
2020
影响因子：
3.3
通讯作者：
F. Clette
中科院分区：
文献类型：
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作者：
F. Clette
F10.7cm射电流量和太阳黑子数是目前应用最广泛的太阳活动长期指标。它们之间有很强的相关性，这导致了许多代理关系的发布，允许将一个指数转换为另一个指数。然而，这些现有的代理人显示出重大分歧，特别是在低太阳活动。此外，最近发现这两个太阳指数的相对尺度存在时间漂移。我们的目标是在全球澄清这些问题。我们计算新的多项式回归到4度，以获得更准确的代理在整个范围内的太阳活动。我们还研究了时间平均对回归的作用，并研究了全安静F10.7背景通量的问题。最后，我们检查了1947-2015年期间F10.7-太阳黑子数关系的任何变化。我们发现，与一个四次多项式，我们得到了一个更准确的代理关系比所有以前发表的，我们推导出一个公式，给出标准误差。日、月和年平均值的关系是不同的，它被证明是完全线性的原始非平均日数据。通过一个简单的每日价值的两个组件模型，我们展示了时间平均如何导致非线性代理关系。我们还表明，安静的太阳F10.7的背景是不是绝对的，实际上取决于一尘不染的时间。最后，我们发现F10.7cm时间序列是不均匀的，在1980年和1981年之间发生了10.5%的突然向上跳跃，并将序列分裂成两个稳定的区间。我们的新代理关系带来了很大的改善，并显示了时间尺度的重要性，选择适当的代理和F10.7安静的太阳背景水平。根据历史证据，我们得出结论，1981年的跳跃很可能是由于F10.7科学团队和数据处理的独特变化，而新重新校准的太阳黑子数（第2版）可能是纠正这种不均匀性的唯一可能参考。
The F10.7cm radio flux and the Sunspot Number are the most widely used long-term indices of solar activity. They are strongly correlated, which led to the publication of many proxy relations allowing to convert one index onto the other. However, those existing proxies show significant disagreements, in particular at low solar activity. Moreover, a temporal drift was recently found in the relative scale of those two solar indices. Our aim is to bring a global clarification of those many issues. We compute new polynomial regressions up to degree 4, in order to obtain a more accurate proxy over the whole range of solar activity. We also study the role of temporal averaging on the regression, and we investigate the issue of the all-quiet F10.7 background flux. Finally, we check for any change in the F10.7–Sunspot Number relation over the entire period 1947–2015. We find that, with a 4th-degree polynomial, we obtain a more accurate proxy relation than all previous published ones, and we derive a formula giving standard errors. The relation is different for daily, monthly and yearly mean values, and it proves to be fully linear for raw non-averaged daily data. By a simple two-component model for daily values, we show how temporal averaging leads to non-linear proxy relations. We also show that the quiet-Sun F10.7 background is not absolute and actually depends on the duration of the spotless periods. Finally, we find that the F10.7cm time series is inhomogeneous, with an abrupt 10.5% upward jump occurring between 1980 and 1981, and splitting the series in two stable intervals. Our new proxy relations bring a strong improvement and show the importance of temporal scale for choosing the appropriate proxy and the F10.7 quiet-Sun background level. From historical evidence, we conclude that the 1981 jump is most likely due to a unique change in the F10.7 scientific team and the data processing, and that the newly re-calibrated sunspot number (version 2) will probably provide the only possible reference to correct this inhomogeneity.