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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]
American sunspot numbers 1945–present; Ancient sunspot data 165 BC to 1684 AD; Group Sunspot Numbers (Doug Hoyt re-evaluation) 1610–1995; Wilson, Robert M. (April 2014). Comparison of the Variations of Sunspot Number, Number of Sunspot Groups, and Sunspot Area, 1875–2013.
The smoothed sunspot number rose again towards this second peak over the last five months of 2016 and surpassed the level of the first peak (66.9 in February 2012). Many cycles are double peaked but this is the first in which the second peak in sunspot number was larger than the first. This was over five years into cycle 24.
Data are acquired by GONG instruments operated by NISP/NSO/AURA/NSF. As of April 2018, the Sun showed signs of a reverse magnetic polarity sunspot appearing and beginning this solar cycle. [21] It is typical during the transition from one cycle to the next to experience a period where sunspots of both polarities exist (during the solar minimum).
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. The biggest difference is an overall increase by a factor of 1.6 to the entire series. Traditionally, a scaling of 0.6 was ...
Sunspot and temperature reconstructions from proxy data. In 2000, Stott and others [72] reported on the most comprehensive model simulations of 20th century climate to that date. Their study looked at both "natural forcing agents" (solar variations and volcanic emissions) as well as "anthropogenic forcing" (greenhouse gases and sulphate aerosols).
Solar cycle 22 was the 22nd solar cycle since 1755, when extensive recording of solar sunspot activity began. [1] [2] The solar cycle lasted 9.9 years, beginning in September 1986 and ending in August 1996. The maximum smoothed sunspot number observed during the solar cycle was 212.5 (November 1989), and the starting minimum was 13.5. [3]