Format Documentation of kpyymm.wdc Files ---------------------------------------------------------------------------- DOI and licence of the Kp dataset Data in the kpyymm.wdc files is based on the Kp dataset. DOI of the Kp dataset: https://doi.org/10.5880/Kp.0001 Kp dataset described in: Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., 2021. The geomagnetic Kp index and derived indices of geomagnetic activity. Space Weather, https://doi.org/10.1029/2020SW002641 Kp dataset publication: Matzka, J., Bronkalla, O., Tornow, K., Elger, K. and Stolle, C., 2021. Geomagnetic Kp index. V. 1.0. GFZ Data Services, https://doi.org/10.5880/Kp.0001 Licence of the dataset and plots: CC BY 4.0 Important Note: DOI and reference publications in March 2021 In March 2021, the Kp dataset was published with a DOI and described in a publication. Important Note: Filename Ambiguity in 2020 Since January 2020, the conventional filenames for the Kp index in the WDC format would have become ambiguous, as Kp2001.wdc could mean a monthly file for January 2020 or a yearly file for the year 2001. From January 2020, all yearly files are moved to a subdirectory called 'yearly'. Please find the updated format description below that takes into account this change. Despite the fact that each line in these WDC files has its own, correct time stamp, we noticed that some of our users, depending on how they reformat the downloaded data files, have produced corrupted files on their side as a consequence of the filename ambiguity and our mitigation step. We recommend our users to check their reformatted files when downloading our WDC files, especially for the early 2000s and the early months of 2020 and especially if they are not sure how their downloading and reformatting algorithm deals with the filename ambiguity. Our other file formats (e.g. *.tab) are not affected. We recommend using daily files, which are updated at the same time as the monthly files. Availability The most recent kpyymm.wdc (yymm stands for year and month, each expressed by two digits) files are distributed half-monthly by the email: kp_index@gfz-potsdam.de Both recent and past files since January 2001 (0101) are distributed from the FTP server: ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/wdc/ FROM 2020 ONWARDS: The yearly files kpyyyy.wdc (yyyy stands for year expressed by four digits) since 1932 are distributed from the FTP server: ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/wdc/yearly/ A description of the FTP server, nowcast indices and background information on geomagnetic indices and the classification of days can be found on the webpage: http://www.gfz-potsdam.de/en/kp-index/ Alternative sources for Kp are: http://www-app3.gfz-potsdam.de/kp_index/qlyymm.wdc (WDC-format in near- real time) tp://ftp.gfz-potsdam.de/home/obs/Kp_ap_Ap_SN_F107 (convenient ASCII format, both archive and near real-time files, near real-time also on:) http://www-app3.gfz-potsdam.de/kp_index/Kp_ap_Ap_SN_F107_nowcast.txt http://www-app3.gfz-potsdam.de/kp_index/Kp_ap_nowcast.txt Preliminaries We use a format similar to the standard format previously used by the National Geophysical Data Center (NGDC) in Boulder, Colorado. Caution: * the columns for the solar radio flux (columns 66-71) are not reported from 2007 onwards * the list of most quiet and most disturbed days is not contained in this format; if you need those, please refer to the other tables (kpyymm.tab) * we do not guarantee the correctness of the international sunspot number R; these values are published separately (Brussels, Belgium) * note that the sunspot number calculation has been changed by WDC-SILSO, Royal Observatory of Belgium, on July 2015, affecting sunspot numbers from January 2015. * sunspot numbers are not reported from 2015 onwards The following format documentation is adapted from: ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/kp_ap.fmt WDC-Format Description The missing data symbol for Kp is 99, the missing data symbol for all other parameters are blanks. Column Format Description ====== ====== =========== 1- 2 i2 yy, last two digits of year 3- 4 i2 mm, month (1-12) 5- 6 i2 dd, day of month (1-31) 7-10 i4 Bartels solar rotation number - a sequence of 27-day intervals counted continuously from February 8, 1832 11-12 i2 Number of day within the Bartels 27-day cycle 13-28 8i2 3-hourly Kp indices (0-3, 3-6, 6-9, 9-12, 12-15, 15-18, 18-21, 21-24 UT) 29-31 i3 Daily Kp sum rounded to thirds, but Ap instead of the daily sum of Kp is recommended for scientific purposes (supplied only for tradition, use Ap scientific purposes!) 32-55 8i3 3-hourly ap indices (0-3, 3-6, 6-9, 9-12, 12-15, 15-18, 18-21, 21-24 UT) 56-58 i3 Ap equivalent daily amplitude, the arithmetic mean of the day's eight ap values rounded to integer 59-61 f3.1 Cp or Planetary Daily Character Figure - a qualitative estimate of overall level of magnetic activity for the day determined from the sum of the eight ap amplitudes. Cp ranges, in steps of one-tenth, from 0 (quiet) to 2.5 (highly disturbed) 62-62 i1 C9 - a conversion of the 0 to 2.5 range of the Cp index to one digit between 0 and 9 63-65 i3 International Sunspot Number. Records contain * Zurich number through December 31, 1980 * International Brussels number thereafter NOT ANY MORE REPORTED FROM 2015 ONWARDS 66-70 f5.1 Ottawa 10.7 cm Solar Radio Flux adjusted to 1 AU - measured at 1700 UT daily and expressed in units of 10^-22 W/m^2/Hz. Observations began on February 14, 1947. From that date through December 31, 1973, the fluxes given here do not reflect the revisions Ottawa made in 1966. NOT ANY MORE REPORTED FROM 2007 ONWARDS 71-71 i1 Flux Qualifier 0: indicates flux required no adjustment; 1: indicates flux required adjustment for burst in progress at time of measurement; 2: indicates a flux approximated by either interpolation or extrapolation; 3: indicates no observation. NOT ANY MORE REPORTED FROM 2007 ONWARDS ---------------------------------------------------------------------------- For questions concerning the data or content of this page, please contact: Juergen Matzka, contact details on http://www.gfz-potsdam.de/en/kp-index/ Last modified: March 15, 2021 Previous modifications: October 8, 2015; April 15, 2020; September 19, 2020