此graph图片可使用矢量图形重新创建为SVG文件。这具有很多好处；更多信息请参见共享资源:待清理媒体。如果存在此图片的SVG格式，请将其上传，然后将此模板替换为{{vector version available|新图片名称}}。 建议您将SVG命名为“Sunspot Numbers.svg”，这样在使用Vector version available（或Vva）模板时就不需要填写新图片名称参数。

This figure summarizes sunspot number observations. Since c. 1749, continuous monthly averages^{[失效链接]} of sunspot activity have been available and are shown here as reported by the Solar Influences Data Analysis Center, World Data Center for the Sunspot Index, at the Royal Observatory of Belgium. These figures are based on an average of measurements from many different observatories around the world. Prior to 1749, sporadic observations of sunspots are available. These were compiled and placed on consistent monthly framework by Hoyt & Schatten (1998a, 1998b).

The most prominent feature of this graph is the c. 11 year solar magnetic cycle which is associated with the natural waxing and waning of solar activity.

On longer time scales, the sun has shown considerable variability, including the long Maunder Minimum when almost no sunspots were observed, the less severe Dalton Minimum, and increased sunspot activity during the last fifty years, known as the Modern Maximum. The causes for these variations are not well understood, but because sunspots and associated faculae affect the brightness of the sun, solar luminosity is lower during periods of low sunspot activity. It is widely believed that the low solar activity during the Maunder Minimum may be among the principal causes of the chilly Little Ice Age, circa 1350-1850 A.D.

This figure was prepared by Robert A. Rohde and is part of the Global Warming Art project.

Image from Global Warming Art

This image is an original work created for Global Warming Art. Please refer to the image description page for more information.

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• Hoyt, D. V., and K. H. Schatten (1998a). "Group sunspot numbers: A new solar activity reconstruction. Part 1.". Solar Physics 179: 189-219.
• Hoyt, D. V., and K. H. Schatten (1998b). "Group sunspot numbers: A new solar activity reconstruction. Part 2.". Solar Physics 181: 491-512.
• Stott, Peter A.; Gareth S. Jones and John F. B. Mitchell (15 December 2003). "Do Models Underestimate the Solar Contribution to Recent Climate Change". Journal of Climate 16: 4079-4093.