Sunspot Index

Monthly Sunspot Counts


sample plot
Correlation Sunspot counts with SLP from 20CRV3
sample plot
Time-series Plotting page
Description
  • Sunspot Count. This is version 2.0.
Specifications
Temporal Coverage
  • Monthly values: 1749 to Aug 2021
  • Update Status: Irregular
Data Notes
  • Units: #
  • Missing data value: -99.0
Get Data
Usage
Usage Restrictions
  • None
Caveats
  • None
Related time-series and links
Related Time-series
Links
Analysis pages that use time-series
Source, References, and Citation
Original Source
  • Data is from SIILSO at their web site.. This is version 1.0. There is an updated version available at their site.
Time-series source dataset(s)
  • N/A
References
  • Please site "credit: Source: WDC-SILSO, Royal Observatory of Belgium, Brussels, `year(s)-of-data'".
  • See https://wwwbis.sidc.be/silso/datafiles
  • Clette, F., Svalgaard, L., Vaquero, J.M., Cliver, E. W., 2014: Revisiting the Sunspot Number. A 400-Year Perspective on the Solar Cycle, Space Science Reviews, Volume 186, Issue 1-4, pp. 35-103. DOI: 10.1007/s11214-014-0074-2 or as an ISSI book: The Solar Activity Cycle, Space Sciences Series of ISSI, Volume 53. ISBN 978-1-4939-2583-4, Springer, pp. 35-103. DOI: 10.1007/978-1-4939-2584-1_3
  • Clette, F., Lefèvre, L., 2016, The New Sunspot Number: assembling all corrections, Solar Physics, 291, DOI: 10.1007/s11207-016-1014-y
  • Clette, F., Lefèvre, L., Cagnotti, M., Cortesi, S., Bulling, A., 2016: The Revised Brussels-Locarno Sunspot Number (1981 - 2015), Solar Physics, 291, DOI: 10.1007/s11207-016-0875-4
  • An entire issue of the Solar Physics Journal is dedicated to the recent recalibration of the Sunspot number:
    • Clette, F., Cliver, E.W., Lefèvre, L, Svalgaard, L., Vaquero, J.M., Leibacher, J.W., 2016: Preface to Topical Issue: Recalibration of the Sunspot Number, Solar Phys., 291, DOI: 10.1007/s11207-016-1017-8