Time range: 1/1992 - last elapsed month (provisional values)

Data description:

Monthly mean North/South sunspot numbers obtained by taking a simple arithmetic mean of the daily North/South sunspot numbers over all days of each calendar month. Each sunspot group is counted in one of the hemispheres based on its heliographic latitude. NB: Hemispheric numbers are always normalized to the corresponding total monthly mean sunspot number (cf. file monthssn.dat)

Error values:

For total numbers, the monthly standard deviation of individual data is derived from the daily values by:

sigma(m)=sqrt(SUM(N(d)*sigma(d)^2)/SUM(N(d)))

where sigma(d) is the standard deviation for a single day and N(d) is the

number of observations for that day.

For hemispheric values, the errors are derived from daily values by:

sigma(m)=sqrt(SUM(sigma(d)^2)/Nobs)

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TXT

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Filename: SN_m_hem_V2.0.txt

Format: plain ASCII text

Contents:

Column 1-2: Gregorian calendar date

- Year

- Month

Column 3: Date in fraction of year for the middle of the corresponding month

Column 4: Monthly mean total sunspot number.

Column 5: North monthly mean sunspot number.

Column 6: South monthly mean sunspot number.

Column 7: Monthly mean standard deviation of total sunspot number data

Column 8: Monthly mean standard deviation of North sunspot number data

Column 9: Monthly mean standard deviation of South sunspot number data

Column 10: Number of observations used to compute the monthly mean total sunspot number.

Column 11: Number of observations for the monthly mean North sunspot number (not used yet)

Column 12: Number of observations for the monthly mean South sunspot number (not used yet)

Column 13: Definitive/provisional marker. A blank indicates that the monthly mean values are definitive. A '*' symbol indicates that the monthly values are still provisional and are subject to a possible revision (Usually the last 3 to 6 months)

Line format [character position]:

- [1-4] Year

- [6-7] Month

- [9-16] Decimal date

- [19-23] Monthly total sunspot number

- [25-29] Monthly north sunspot number

- [31-35] Monthly south sunspot number

- [38-42] Standard deviation (Total)

- [44-48] Standard deviation (North)

- [50-54] Standard deviation (South)

- [57-60] Number of observations (Total)

- [62-65] Number of observations (North)

- [67-70] Number of observations (South)

- [72] Definitive/provisional indicator

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CSV

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Filename: SN_m_hem_V2.0.csv (adapted for import in spreadsheets)

The separator is the semicolon ';'.

Format: Comma Separated values

Contents:

Column 1-2: Gregorian calendar date

- Year

- Month

Column 3: Date in fraction of year for the middle of the corresponding month (day 15)

Column 4: Monthly mean total sunspot number.

Column 5: North monthly mean sunspot number.

Column 6: South monthly mean sunspot number.

Column 7: Monthly mean standard deviation of total sunspot number data

Column 8: Monthly mean standard deviation of North sunspot number data

Column 9: Monthly mean standard deviation of South sunspot number data

Column 10: Number of observations for the monthly mean total sunspot number.

Column 11: Number of observations for the monthly mean north sunspot number (not used yet)

Column 12: Number of observations for the monthly mean south sunspot number (not used yet)

Column 13: Definitive/provisional marker. '1' indicates that the value is definitive. '0' indicates that the value is still provisional.

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LICENSE

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SILSO data is under CC BY-NC4.0 license (https://goo.gl/PXrLYd) which means you can :

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