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The international sunspot number series extends back to 1700 with annual values while daily values exist only since 1818. Since 1 July 2015 a revised and updated international sunspot number series has been made available. [5] The biggest difference is an overall increase by a factor of 1.6 to the entire series. Traditionally, a scaling of 0.6 ...
Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. [1]
Changes in carbon-14 concentration in the Earth's atmosphere, which serves as a long term proxy of solar activity.. This figure summarizes sunspot number observations. Since c. 1749, continuous monthly averages 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 ...
Solar cycle 23 lasted 11.6 years, beginning in May 1996 and ending in January 2008. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle was 120.8 (March 2000), and the minimum was 1.7. [29] A total of 805 days had no sunspots during this cycle. [30] [31] [32]
International Sunspot Number – sunspot maximum and minimum 1610–present; annual numbers 1700–present; monthly numbers 1749–present; daily values 1818–present; and sunspot numbers by north and south hemisphere. The McNish–Lincoln sunspot prediction is also included. American sunspot numbers 1945–present
English: The daily sunspot number from 1945-01-02 to 2017-06-30, and its power spectral analysis. There are two prominent peaks corresponding to its 27-day cycle and 11-year cycle. See "The 27-day signal in sunspot number series and the solar dynamo" (JL Le Mouël, MG Shnirman, EM Blanter - Solar Physics, 2007)
Earlier this month, NOAA reported that preliminary observations had found 299 sunspots that all appeared within 24 hours — the highest daily sunspot record in over 22 years if confirmed.
Solar activity has been on a declining trend since the 1960s, as indicated by solar cycles 19–24, in which the maximum number of sunspots were 201, 111, 165, 159, 121 and 82, respectively. [14] In the three decades following 1978, the combination of solar and volcanic activity is estimated to have had a slight cooling influence. [ 15 ]