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The sunspot areas and the relative sunspot numbers

Geofisica pura e applicata, 1960
Within each sunspot cycle the yearly means (A) of the daily sunspot areas increase faster than the corresponding sunspot numbers (R) from the minimum to the maximum of solar activity and then decrease also faster than these numbers till the next minimum.
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Prediction of sunspot numbers

Eos, Transactions American Geophysical Union, 1949
A formula for predicting smoothed annual sunspot numbers is developed. A first approximation to the prediction of a future value in a cycle is the mean of all past values for that part of the cycle. This estimate can be improved by adding to the mean a correction proportional to the departure of earlier values of the cycle from the mean cycle.
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The Sunspot Number Series

Nature, 1953
SUNSPOT numbers form a quasi-periodic series (see Fig. 1, upper curve) going back for eighteen cycles to 1750. Very numerous attempts have been made to analyse the series, with little success. It does not appear to contain a truly periodic term, as do tides and weather records.
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On the average rate of growth in sunspot number and the size of the sunspot cycle

Solar Physics, 1990
The average rate of growth in sunspot number over selected time intervals and the maximum average value as they both relate to the size of the cycle are examined, in order to predict the size of cycle 22. The predictions are compared with those of Wilson (1990) to determine whether a consensus is apparent.
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Wavelet analysis of sunspot numbers

Chinese Astronomy and Astrophysics, 1998
Abstract The principle of detecting singularities in the signal using wavelet transform is discussed. The yearly mean sunspot numbers during 1700–1993 are analyzed by this technique and the individual periods of sunspot activity are determined, as dinstinct from the tranditional method.
Bo Feng, Xi-zheng Ke, Hua-ling Ding
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An estimate of the peak sunspot number in 1968

Journal of Atmospheric and Terrestrial Physics, 1960
Abstract An examination has been made of some statistical properties of the twenty peaks in the relative sunspot number which have occurred since 1750. The frequency distributions of R and ΔR and the autocorrelation function have made it possible to forecast the magnitude of the next peak which will probably occur in about 1968.
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Monthly Mean Sunspot Numbers

1985
Daily relative sunspot numbers are based upon counts of spots and group entities of spots on the sun’s surface at some time each day. Wolf devised a relative number with the intent of reducing the spot counts of different observers and telescopes to a common basis.
D. F. Andrews, A. M. Herzberg
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On the statistics of maximum sunspot numbers

Journal of Atmospheric and Solar-Terrestrial Physics, 1998
Abstract On the basis of the statistics of extremes (i.e. Gumbels first asymptotic distribution)and the characteristics of cycles 9–22 (the most reliable sunspot cycles) the magnitude of the cyclepeaks is studied. The analysis is based on the quasi-periodic solar activity which has a main periodof approximately 22 years.
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Sunspot Number and the Refractivity of the Air

Nature, 1934
IN connexion with the note by L. W. Tilton on the relation between the sunspot number and refractivity of dry air1, it is of interest to examine whether such a relation may be deduced from the astronomical observations. For this purpose we have selected twenty independent determinations of the refraction constant () and reduced them to 0° C., 760 mm ...
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Rome rainfall and sunspot numbers

Journal of Atmospheric and Terrestrial Physics, 1993
Abstract The accumulated departure from mean (ADM) of the 208 yr Rome rainfall strongly inversely resembles the ADM of sunspot numbers. The ADM for the Bay of Biscay sea surface temperature also strongly resembles sunspot numbers and Rome rainfall. These data suggest that long-term increasing solar radiation warms parts of the North Atlantic Ocean ...
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