Reconstruction of the Sunspot Group Number: The Backbone Method

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• 作者：Leif Svalgaard ; Kenneth H. Schatten
• 关键词：Solar Cycle ; Reconstruction ; Sunspot Group Number
• 刊名：Solar Physics
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：291
• 期：9-10
• 页码：2653-2684
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Astrophysics and Astroparticles; Atmospheric Sciences; Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics);
• 出版者：Springer Netherlands
• ISSN：1573-093X
• 卷排序：291

文摘

We have reconstructed the sunspot-group count, not by comparisons with other reconstructions and correcting those where they were deemed to be deficient, but by a re-assessment of original sources. The resulting series is a pure solar index and does not rely on input from other proxies, e.g. radionuclides, auroral sightings, or geomagnetic records. “Backboning” the data sets, our chosen method, provides substance and rigidity by using long-time observers as a stiffness character. Solar activity, as defined by the Group Number, appears to reach and sustain for extended intervals of time the same level in each of the last three centuries since 1700 and the past several decades do not seem to have been exceptionally active, contrary to what is often claimed.