文摘
In this paper, we construct a time series knownas the Group Sunspot Number. TheGroup Sunspot Number is designed to be more internallyself-consistent (i.e., less dependent upon seeing the tiniest spots)and less noisy than theWolf Sunspot Number. It uses the number of sunspot groupsobserved, rather than groups andindividual sunspots. Daily, monthly, and yearly means arederived from 1610 to the present. TheGroup Sunspot Numbers use 65941 observations from 117observers active before 1874 thatwere not used by Wolf in constructing his time series. Hence,we have calculated daily values ofsolar activity on 111358 days for1610–1995, compared to66168 days for the Wolf SunspotNumbers. The Group Sunspot Numbers also have estimates oftheir random and systematicerrors tabulated. The generation and preliminary analysis ofthe Group Sunspot Numbers allowus to make several conclusions: (1) Solar activity before 1882 islower than generally assumedand consequently solar activity in the last few decadesis higher than it has been for severalcenturies. (2) There was a solar activity peak in1801 and not 1805 so there is no long anomalouscycle of 17 years as reported in the Wolf Sunspot Numbers. Thelongest cycle now lasts no morethan 15 years. (3) The Wolf Sunspot Numbers have manyinhomogeneities in them arising fromobserver noise and this noise affects the daily, monthly,and yearly means. The Group SunspotNumbers also have observer noise, but it is considerablyless than the noise in the Wolf SunspotNumbers. The Group Sunspot Number is designed to besimilar to the Wolf Sunspot Number,but, even if both indices had perfect inputs, some differencesare expected, primarily in the dailyvalues.
