Uccle hemispheric sunspot numbers

Uccle hemispheric sunspot numbers

Monthly mean and smoothed sunspot numbers for the North and South hemispheres of the Sun, derived from the sunspot drawing series of the Uccle solar station from 1950 to 1994.
As those data come from a single station, the numbers are not available for all days (about 75% time coverage). Therefore, only monthly means were derived, and they are only an approximation of the monthly means over all days. The relative North and South numbers were normalized to the international total sunspot number (Version 2): the sum for the North and South numbers was set equal to the international total number by scaling both hemispheric values by the same factor.
This file can be used to extend the international hemispheric sunspot numbers, which were only started in Januray 1992 and are based on the statistical processing of the numbers for our worldwide network of stations. There is a 2.5 year overlap between the two series between 1992 and 1994. The accuracy of the Uccle numbers is lower than the more recent hemispheric numbers derived from a large number of stations. However, they provide a fair approximation over several cycles before 1992.

Structure of the file:
Column 1: Year
Column 2: Month
Column 3: Date in year and fraction of year
Column 4: Total monthly mean sunspot number
Column 5: North monthly mean sunspot number
Column 6: South monthly mean sunspot number
Column 7: Total 13-month smoothed mean sunspot number
Column 8: North 13-month smoothed mean sunspot number
Column 9: South 13-month smoothed mean sunspot number