Indices of Global Geomagnetic Activity -------------------------------------- Geomagnetic Kp Index The planetary three-hour-range Kp index was introduced by J. Bartels in 1949 and is derived from the standardized K index (Ks) of 13 magnetic observatories. It is designed to measure solar particle radiation by its magnetic effects. Musical Kp Diagram The most popular representation of the Kp indices is in form of the Bartels musical diagram (musical scales). Geomagnetic ap, Ap, Cp and C9 Indices The geomagnetic ap, Ap, Cp and C9 indices and the classification of international Q-days and D-days are derived from the Kp index. Related Indices Km is an index similar to Kp, except for the different number and selection of stations and the method of averaging. The indices am and Am are similar to ap and Ap. Km, am and Am are evaluated at l'Institut de Physique du Globe in Paris, France. References * J. Bartels, The technique of scaling indices K and Q of geomagnetic activity, Ann. Intern. Geophys. Year 4, 215-226, 1957; * J. Bartels,The geomagnetic measures for the time-variations of solar corpuscular radiation, described for use in correlation studies in other geophysical fields, Ann. Intern. Geophys. Year 4, 227-236, 1957; * M. Siebert, Masszahlen der erdmagnetischen Aktivitaet, in Handbuch der Physik, vol. 49/3, 206-275, Springer, Berlin Heidelberg, 1971; for the description of several indices (in German); * M. Siebert and J. Meyer, Geomagnetic Activity Indices, in The Upper Atmosphere (Eds. W. Dieminger et al.), 887-911, Springer, Berlin Heidelberg, 1996; for an updated version of the German reference; * P.N. Mayaud, Derivation, Meaning and Use of Geomagnetic Indices, Geophysical Monograph 22, Am. Geophys. Union, Washington D.C., 1980; for a complete review of the present IAGA indices; * G.K. Rangarajan, Indices of magnetic activity, in Geomagnetism, edited by I.A. Jacobs, Academic, San Diego, 1989; * M. Menvielle and A. Berthelier, The K-derived planetary indices: description and availability, Rev. Geophys. 29, 3, 415-432, 1991. Sources of Kp and derived indices * Beginning January 1997: GeoForschungsZentrum Potsdam Adolf-Schmidt-Observatorium fuer Geomagnetismus Lindenstrasse 7 D-14823 Niemegk Germany o E-mail distribution (contact Dr. H.-J. Linthe, mailto:kp_index@gfz-potsdam.de) o IUGG/IAGA International Service of Geomagnetic Indices (monthly letter) * Ending January 1997: Institut fuer Geophysik Universitaet Goettingen Postfach 2341 D-37013 Goettingen Germany o E-mail distribution (contact Rainer Hennings, mailto:rhennin@gwdg.de ) o FTP server (two-weekly update) o IUGG/IAGA International Service of Geomagnetic Indices (monthly letter) * World Data Center C1 for Geomagnetism Danish Meteorological Institute Lyngbyvej 100 DK-2100 Copenhagen OE Denmark o FTP server (two-weekly update) * World Data Center A for Solar-Terrestrial Physics 325 Broadway Boulder, CO 80303-3328 U.S.A. o FTP server: ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/ (monthly update) o Solar-Geophysical Data Reports (monthly) Editor: Helen E. Coffey (hec@ngdc.noaa.gov) o Solar Indices Bulletin (prompt monthly report) o Magnetic tapes and CD-ROMs * National Space Science Data Center 7701 Greenbelt Rd. Suite 400 Greenbelt, MD 20770 U.S.A. o OMNIWeb (WWW-based data retrieval and analysis system) o Solar-Terrestrial Indices on CD-ROM, Diskette and Tape * IAGA Bulletin No. 32 (yearly compilation, irregular publication date) Structure of the FTP sites As a member of the International Service of Geomagnetic Indices, the GeoForschungsZentrum, Adolf-Schmidt-Observatory in Niemegk supplies historical and current Kp and derived indices per anonymous FTP. Two FTP servers with identical structure are available: Denmark: ftp://ftp.dmi.min.dk/pub/Data/WDCC1/indices/kp-ap/ Germany: ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/ (WWW access: http://www.gfz-potsdam.de/pub/home/obs/kp-ap/) Note: FTP sites may refuse connections due to excessive traffic. Your mileage may vary with a different FTP program. The kp-ap/ directory contains readme.txt (text file) A plain text copy of the Geomagnetic Indices WWW page. music.exe (binary executable file) A PC executable program for 386 or higher machines. music.exe reads Kp/ap values in WDC format and produces a PostScript file with Bartels Kp music diagram. Download music.exe using binary mode! The data file ssc.dat is also required to run music.exe. ssc.dat (text data file) List of sudden commencements (ssc), partly preliminary. tab/ (subdirectory) contains the monthly Kp/ap tables in a simple text format readable for both humans and computers (*.tab). The file tab_fmt.doc provides a format description. The tables distributed by regular mail (PostScript format) are also provided in this directory. wdc/ (subdirectory) contains the monthly (respectively yearly) Kp/ap tables and much more information in condensed tables (ASCII format). The format is nearly identical to the format of Kp/ap tables distributed by the World Data Center A for Solar-Terrestrial Physics. The file wdc_fmt.doc provides a format description. This format does not contain any information on the quiet and most disturbed days as the tables in the tab directory do. music/ (subdirectory) contains the Kp values in the Bartels musical diagram (PostScript format), which is very helpful in visualizing the indices. quietdst/ (subdirectory) contains tables of the quietest and most disturbed days for all months since Jan 1932. (Values since 1900 also supplied, use with caution.) kp-freq/ (subdirectory) contains tables of frequencies of Kp indices. ap_monyr.ave (text file) A table with monthly and yearly averages of Ap. ---------------------------------------------------------------------------- URL: http://www.gfz-potsdam.de/~kp_index/ Last modified: Fri Feb 07 14:46:37 MET 1997