NOAA/NESDIS/NGDC/STP, Boulder-Sunspot Number Data …

1 Search NGDCS earch NOAAGo noaa > NESDIS > ngdc > STP > Space Weathercomments | privacy policy STPS olarFTPSPIDR What's New FAQ STP HomeSolar Data HomeOnline PublicationsFTP AccessSPIDRNGDC Technical Data ServicesWhat's NewFAQM ailing Address:National Geophysical Data CenterSolar and Terrestrial PhysicsDivision325 BroadwayBoulder, CO 80305-3328 USADr. William F. Denig, Chief NumbersToday, much more sophisticated measurements of solar activity are maderoutinely, but none has the link with the past that sunspot numbers have. McKinnonInternational Sunspot Number - Brief Descriptionsunspot maximum and minimum 1610-present; annual numbers1700-present; monthly numbers 1749-present; daily values1818-present; and sunspot numbers by north and south McNish-Lincoln sunspot prediction is also included.

2 ---- DownloaddataRelative Sunspot Numbers -- The collection of sunspot numbersprovided here contains several kinds of tables -- tables that give spotcounts averaged over different time intervals. Professor M. Waldmeier,Director of the Swiss Federal Observatory in Zurich, Switzerland,published these observations in 1961 as a book entitled THE SUNSPOT-ACTIVITY IN THE YEARS 1610-1960 (Zurich Schulthess and CompanyAG) and updated more recently by the Royal Observatory of Belgium'sSolar Influences Data Analysis relative sunspot Number is an index of the activity of the entirevisible disk of the Sun. It is determined each day without reference topreceding days. Each isolated cluster of sunspots is termed a sunspotgroup, and it may consist of one or a large Number of distinct spotswhose size can range from 10 or more square degrees of the solarsurface down to the limit of resolution ( , 1/25 square degree).

3 Therelative sunspot Number is defined as R = K (10g + s), where g is thenumber of sunspot groups and s is the total Number of distinct scale factor K (usually less than unity) depends on the observer andis intended to effect the conversion to the scale originated by provisional daily Zurich relative sunspot numbers, Rz, were basedupon observations made at Zurich and its two branch stations in Arosaand Locarno and communicated by M. Waldmeier of the Swiss FederalObservatory. Beginning January 1, 1981, the Zurich relative sunspotnumber program is replaced by the Solar Influences Data AnalysisCenter (formerly the Sunspot Index Data Center) (c/o Dr. R. Van derLinden, 3 av.)

4 Circulaire, B-118 Bruxelles, Belgium). The determinationof the provisional International Sunspot Numbers Ri results from , Boulder-Sunspot Number Data from of 46/30/2013 5:17 PMstatistical treatment of the data originating from more than twenty-fiveobserving stations. These stations constitute an international network,with the Locarno (Switzerland) station as the reference station, toguarantee continuity with the past Zurich series of Rz. The definitiveInternational Sunspot Numbers Ri are evaluated by a similar methodbased on a network of observing stations selected for their high numberof observations, their continuity during the whole year and an existingseries of observations during the last years.

5 Also taken into account isthe stability of the K monthly factors with reference to the Locarnostation. These relative sunspot numbers are now designated Ri(International) instead of Rz (Zurich).The international sunspot Number is produced by the Solar InfluencesData Analysis Center (SIDC), World Data Center for the Sunspot Index,at the Royal Observatory of Belgium. ngdc kindly requests that youacknowledge the SIDC when using these data. Please refer to the SIDC site for additional information. The SIDC requests users of the data tocredit: SIDC, RWC Belgium, World Data Center for the Sunspot Index,Royal Observatory of Belgium, `year(s)-of-data'.Sunspot Numbers by Hemisphere.

6 (1992-1996) ---- Download Relative Sunspot Numbers ---- Download DataBeginning with 1951, the observations collected by the Solar Division,AAVSO, have been reduced according to a new procedure, such thatonly high quality observations of experienced observers are combinedinto RA'. Observatory co- efficients for each of the 23 selected observerswere recomputed on data for 1948-1950, years when there was a widerange of solar activity. Otherwise, the procedure is that outlined in"Publication of the Astronomical Society of the Pacific," "61," 13, scale of the American numbers in 1951 will differ from that of thereports for earlier years because of these changes, and the new series isdesignated RA' rather than sunspot data 165 to 1684 Catalogue of sunspot observations from 165 BC to AD 1684(text) -- AbstractCatalogue of Naked-Eye Sunspot Observations and LargeSunspots (text)Estimated annual mean sunspot Number , R, from 1610-1715(text) Sunspot Numbers (Doug Hoyt re-evaluation)

7 1610-1995 Descriptive text about data files -- print before viewing data fordata formatsFiles can be grouped into five categories -- input, means, , Boulder-Sunspot Number Data from of 46/30/2013 5:17 PMstandard deviations, Number of observations, anddocumentation files4a. Input files -- alldata (raw daily input data for463 observers) and filldata (raw data data withsome missing days filled by linear interpolation)4aa. alldata4ab. filldata4b. Means files -- , -- contains daily values ofthe Group Sunspot Numbers for 1610 to 19954bb. -- contains monthly meansof Rg with the Number of days used to formthe means and the standard deviation of themeans4bc.

8 -- contains yearly means ofRg with the Number of days used to form themeans and the standard deviation of themeans4c. Standard deviation files -- , and -- contains daily standarddeviations of the Group Sunspot Numbers for1610 to 1995. These numbers represent therandom errors in the daily -- contains the monthlymeans of daily standard deviations -- contains the yearly meansof monthly standard deviations Number of observations files -- , and -- contains the dailynumber of observations per day used informing the daily -- contains the monthlyaverage Number of observations per day usedin forming the daily -- contains the yearlyaverage Number of observations per day usedin forming the daily Documentation files -- , , and -- An inventory file listing theobserver Number , his observation year, andNOAA/NESDIS/ ngdc /STP.

9 Boulder-Sunspot Number Data from of 46/30/2013 5:17 PMnumber of days of -- A summary of the 463observers used to reconstruct solar -- A bibliography listing theliterature source of each observer used alongwith appropriate comments. Also listed aresome observers identified but not used forone reason or -- A list of the calculatedobserver correction factors used to place theobserver on the Royal Greenwich Observatory(RGO) scale. These factors make all theobservers as self-consistent as > NESDIS > ngdc > STP > Space WeatherQuestions: Home | Contacts | Data | Disclaimers | Education | News | Privacy Policy | Site MapNOAA/NESDIS/ ngdc /STP, Boulder-Sunspot Number Data from of 46/30/2013 5:17 PM