============================================================= == Solar Flux and Geomagnetic Indices in STK Applications == ============================================================= ======================= = Updates/Changes = ======================= Feb. 2010: These files were missing data from 20051001 to 20051231 which has now been included by copying the data from the stkNewFluxGeoMag.fxm file. The copied data includes changes to the average F10 values before and after the missing dates. Sept. 2004: Our ftp site name has changed, as has the location of these files on the ftp site. These files are now stored at: ftp://ftp.agi.com/pub/DynamicEarthData Sept. 2004: Added ability to read observed ap or Kp values by using a new keyword. Look under the section titled "Listing of modified kp_ap.fmt" and look for the keyword ReadApOrKp. July 2004: Added flux files to our ftp site which contain daily measured values and daily updates to predicted data. See the section below titled "Daily Observed Data". ======================= = General Information = ======================= File Versions and Data Spans: ----------------------------- There are two files--as of November 2000--that contain solar flux and geomagnetic indices for use by Astrogator/HPOP in STK as well as in OD Tool Kit: 1. stkFluxGeoMag.fxm 2. stkFluxGeoMag.5yr.fxm File #1 is the master file and contains data from 1953 to present. File #2 is a shortened version of this file, with observed data from only the last five years (1827 days). The starting date of this file changes such that the total number of days of observed data in the file stays constant. For ephemeris generation of satellites within the last five years, the stkFluxGeoMag.5yr.fxm file should be used, as it will be processed much quicker than the master file. For the quickest processing speed possible, the master file should be copied and edited to contain data for the time period you are interested in. The first eight digits of each "Observed" record are given in yyyymmdd format. For example, the record beginning 19920501 corresponds to May 1, 1992. If you wanted to model a satellite that was operational from March 1994 to June 1998, you should copy the master file and edit it to remove Observed records from 1953 to 1994. (Removing records for dates following the end of the time span you are interested in will have little to no effect on the processing speed.) Observed and Predicted Data Sources: ------------------------------------ New observed values are added in one-month blocks as they become available. These observed values come from files named [YYYY].v[X], where [YYYY] is the year and [X] is the month numbered 1-12, which are from the ftp site: ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP These files are generated monthly and contain observed data for the previous month. Besides observed data, the stkFluxGeoMag.fxm file also contains predictions for F10.7 and Ap. This prediction data (F10.7 and AP predictions) come from the file "45DF.txt" located at: ftp://ftp.sel.noaa.gov/pub/latest/ Data Latency: ------------- The 45 day predict file is updated daily, and the observed values are updated monthly. This means that on the day the observed values are added to the file, there are 45 days of predicted values. On the next day the 45 days of predicted data are added into our file such that there are now 46 days of predicted data, with the first day of predicted data being one day old. In 10 days, there will be 55 days of predicted data, and the first day of predicted data will be 10 days old. FTP Site and Login Information: ------------------------------- The stk flux files are being updated daily on the AGI ftp site. The location of these files is: ftp://ftp.agi.com/pub/DynamicEarthData You may log in to our ftp site using the login name "anonymous" and using your email address as the password. ======================================== = Format of the stkFluxGeoMag.fxm file = ======================================== The stkFluxGeoMag.fxm file contains three sections of data, separated by "BEGIN' and 'END' records. The three sections include observed solar flux/ geomagnetic indices data, predicted flux data, and predicted geomagnetic indexes. The sections are designated by the following keywords, and must be given in this order: BEGIN OBSERVED END OBSERVED BEGIN F10_PREDICT END F10_PREDICT BEGIN AP_PREDICT END AP_PREDICT Observed Values --------------- These observed values come from files named [YYYY].v[X], where [YYYY] is the year and [X] is the month numbered 1-12, which are from the ftp site: ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP The latest two files, for example, are named "2003" and "2004.v8". The format of this file is given on the ftp site in the file named 'kp_ap.fmt'. The main difference between the stkFluxGeoMag.fxm file used in STK and these raw data files are: 1. We use a 4-digit year instead of a 2-digit year, and 2. We add an 81-day averaged F10.7 value at the end of each line. Since we change the year to four digits by adding two additional columns, the column designations in the 'kp_ap.fmt' file do not match what we use. I have listed below a modified version of the 'kp_ap.fmt' file with the column designations corrected to match the stkFluxGeoMag.fxm file. Listing of modified kp_ap.fmt: ------------------------------ The National Geophysical Data Center provides the observations here with no re- strictions on their use. Please contact us at the address below with your com- ments and questions about the form and the content of this information product or about the measurements themselves. NATIONAL GEOPHYSICAL DATA CENTER 325 Broadway Mail Code E/GC2 Boulder, Colorado 80303-3328 USA Telephone: (303) 497-6475 Telex: 592811 NOAA MASC BDR FAX: (303) 497-6513 ------------------------------------------------------------------------------- SELECTED GEOMAGNETIC AND SOLAR ACTIVITY INDICES ------------------------------------------------------------------------------- WORLDWIDE INDICES-------------------------------------------------------------- The subscript "p" means planetary and designates a global magnetic activity in- dex. The following 13 observatories, which lie between 46 and 63 degrees north and south geomagnetic latitude, now contribute to the planetary indices: Ler- wick (UK), Eskdalemuir (UK), Hartland (UK), Ottawa (Canada), Fredericksburg (USA), Meannook (Canada), Sitka (USA), Eyrewell (New Zealand), Canberra (Aus- tralia), Lovo (Sweden), Brorfelde (Denmark), Wingst (Germany), and Niemegk (Germany). THREE-HOUR-RANGE INDEX K------------------------------------------------------- K indices isolate solar particle effects on the earth's magnetic field; over a 3-hour period, they classify into disturbance levels the range of variation of the more unsettled horizontal field component. Each activity level relates al- most logarithmically to its corresponding disturbance amplitude. Three-hour indices discriminate conservatively between true magnetic field perturbations and the quiet-day variations produced by ionospheric currents. K indices range in 28 steps from 0 (quiet) to 9 (greatly disturbed) with frac- tional parts expressed in thirds of a unit. A K-value equal to 27, for exam- ple, means 2 and 2/3 or 3-; a K-value equal to 30 means 3 and 0/3 or 3 exactly; and a K-value equal to 33 means 3 and 1/3 or 3+. The arithmetic mean of the K values scaled at the 13 observatories listed above gives Kp. EQUIVALENT AMPLITUDE----------------------------------------------------------- The a-index ranges from 0 to 400 and represents a K-value converted to a linear scale in gammas (nanoTeslas)--a scale that measures equivalent disturbance am- plitude of a station at which K=9 has a lower limit of 400 gammas. FORMAT FOR RECORDS OF SELECTED GEOMAGNETIC AND SOLAR ACTIVITY INDICES (NOTE: Column numbers have been altered to match the stkFluxGeoMag.fxm file) ------------------------------------------------------------------------------- COLUMNS FMT DESCRIPTION ------------------------------------------------------------------------------- 1- 4 I4 YEAR 5- 6 I2 MONTH 7- 8 I2 DAY 9-12 I4 BARTELS SOLAR ROTATION NUMBER--a sequence of 27-day intervals counted continuously from February 8, 1832. 13-14 I2 NUMBER OF DAY within the Bartels 27-day cycle. 15-16 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0000 - 0300 UT. 17-18 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0300 - 0600 UT. 19-20 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0600 - 0900 UT. 21-22 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0900 - 1200 UT. 23-24 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 1200 - 1500 UT. 25-26 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 1500 - 1800 UT. 27-28 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 1800 - 2100 UT. 29-30 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 2100 - 2400 UT. 31-33 I3 SUM of the eight Kp indices for the day expressed to the near- est third of a unit. 34-36 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0000 - 0300 UT. 37-39 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0300 - 0600 UT. 40-42 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0600 - 0900 UT. 43-45 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0900 - 1200 UT. 46-48 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 1200 - 1500 UT. 49-51 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 1500 - 1800 UT. 52-54 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 1800 - 2100 UT. 55-57 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 2100 - 2400 UT. 58-60 I3 Ap or PLANETARY EQUIVALENT DAILY AMPLITUDE--the arithmetic mean of the day's eight ap values. 61-63 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). 64-64 I1 C9--a conversion of the 0-to-2.5 range of the Cp index to one digit between 0 and 9. 65-67 I3 INTERNATIONAL SUNSPOT NUMBER. Records contain the Zurich num- ber through December 31, 1980, and the International Brus- sels number thereafter. 68-72 F5.1 OTTAWA 10.7-CM SOLAR RADIO FLUX ADJUSTED TO 1 AU--measured at 1700 UT daily and expressed in units of 10 to the -22 Watts/ meter sq/hertz. Observations began on February 14, 1947. From that date through December 31, 1973, the fluxes given here don't reflect the revisions Ottawa made in 1966. 73-73 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; and "3" indicates no observation. 74-78 F5.1 F10.7 81-day Average, based on F10.7 daily data taken from 40 days prior to 40 days following. If there is not data for 40 days following, whatever data is available is used. ------------------------------------------------------------------------------- End of 'kp_ap.fmt' listing ------------------------------------------------------------------------------- You will note that geomagnetic indices are given in both Kp and ap values. By default, we read the Kp values. However, you can add a keyword into this file to force the reading of the ap values. To read observed ap values, make the first line in the file (before the BEGIN OBSERVED line): ReadApOrKp Ap and to read Kp, the default, either remove the line or change Ap to Kp: ReadApOrKp Kp Besides using only ap or Kp but not both, not all of the observed data is used. Here is a stripped down description, and all other columns can be empty: ------------------------------------------------------------------------------- COLUMNS FMT DESCRIPTION ------------------------------------------------------------------------------- 1- 4 I4 YEAR 5- 6 I2 MONTH 7- 8 I2 DAY (if reading Kp, otherwise ignore) 15-16 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0000 - 0300 UT. 17-18 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0300 - 0600 UT. 19-20 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0600 - 0900 UT. 21-22 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 0900 - 1200 UT. 23-24 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 1200 - 1500 UT. 25-26 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 1500 - 1800 UT. 27-28 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 1800 - 2100 UT. 29-30 I2 Kp or PLANETARY 3-HOUR RANGE INDEX for 2100 - 2400 UT. 31-33 I3 SUM of the eight Kp indices for the day expressed to the near- est third of a unit. (if reading ap, otherwise ignore) 34-36 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0000 - 0300 UT. 37-39 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0300 - 0600 UT. 40-42 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0600 - 0900 UT. 43-45 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 0900 - 1200 UT. 46-48 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 1200 - 1500 UT. 49-51 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 1500 - 1800 UT. 52-54 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 1800 - 2100 UT. 55-57 I3 ap or PLANETARY EQUIVALENT AMPLITUDE for 2100 - 2400 UT. 58-60 I3 Ap or PLANETARY EQUIVALENT DAILY AMPLITUDE--the arithmetic mean of the day's eight ap values. 68-72 F5.1 OTTAWA 10.7-CM SOLAR RADIO FLUX ADJUSTED TO 1 AU--measured at 1700 UT daily and expressed in units of 10 to the -22 Watts/ meter sq/hertz. Observations began on February 14, 1947. From that date through December 31, 1973, the fluxes given here don't reflect the revisions Ottawa made in 1966. 74-78 F5.1 F10.7 81-day Average, based on F10.7 daily data taken from 40 days prior to 40 days following. If there is not data for 40 days following, whatever data is available is used. ------------------------------------------------------------------------------- The following is an example of a line from the stkFluxGeoMag.fxm file with the column designations shown: 0 1 2 3 4 5 6 7 123456789012345678901234567890123456789012345678901234567890123456789012345678 200009292282 92023 72320171717143 7 9 3 9 7 6 6 6 70.31119192.60171.7 or the equivalent stripped down version, showing only the required data, is: 20000929 2023 72320171717 192.6 172.7 Predicted Values ---------------- Besides observed data, the stkFluxGeoMag.fxm file also contains predictions for F10.7 and Ap. This prediction data (F10.7 and AP predictions) come from the file "45DF.txt" located at: ftp://ftp.sel.noaa.gov/pub/latest/ The format for the F10 predict section, as used in the stkFluxGeoMag.fxm file, is: ------------------------------------------------------------------------------- COLUMNS FMT DESCRIPTION ------------------------------------------------------------------------------- 1- 4 I4 YEAR 5- 6 I2 MONTH 7- 8 I2 DAY 9- 9 1X blank space 10-12 I3 F10.7 Prediction value 13-13 1X blank space 14-18 F5.1 81-day F10.7 average ------------------------------------------------------------------------------- The format for the Ap prediction section is: ------------------------------------------------------------------------------- COLUMNS FMT DESCRIPTION ------------------------------------------------------------------------------- 1- 4 I4 YEAR 5- 6 I2 MONTH 7- 8 I2 DAY 9- 9 1X blank space 10-12 I3 Ap Prediction value ------------------------------------------------------------------------------- Values read from the stkFluxGeoMag file --------------------------------------- The values from each Observed line that are actually read and used by STK from the flux file are the year, month, day, Kp (or ap) values, F10.7 and F10.7 81- day average. All of the predicted data is used. The predicted Ap values are converted to Kp values internally to STK. Daily Observed Data ------------------- The section for "OBSERVED" data can be augmented with daily measured data. We keep a version of these files on our ftp site which contain daily measurements of Kp values: ftp://ftp.agi.com/pub/DynamicEarthData/stkNewFluxGeoMag.fxm and ftp://ftp.agi.com/pub/DynamicEarthData/stkNewFluxGeoMag.5yr.fxm We put a letter 'd' in column 73 to indicate daily values. We replace these daily values with the measured monthly values when they become available. These values are updated three times per day by retrieving values from the following files: http://sec.noaa.gov/ftpdir/latest/curind.txt http://sec.noaa.gov/ftpdir/latest/dayind.txt Summary ------- The following listing shows sample segments of an stkFluxGeoMag.fxm file, showing how the "BEGIN" and "END" records are used to differentiate between observed and predicted data sections. Each section may contain as many records as needed or are available. BEGIN OBSERVED 1953021016372620 3 31330303347180 7 2 2 5 15 15 18 39 130.73 13 77.00 51.2 195302111637273727302717 72020183 22 12 15 12 6 3 7 7 100.63 13 77.00 52.0 195302121638 110131317172017 3110 4 5 5 6 6 7 6 2 50.21 7 74.00 51.1 . . . 200306282305253047336357474047363 15 39 18 94 67 39 27 39 421.57 93128.10128.9 200306292305263733404733373740303 22 18 27 39 18 22 22 27 241.26 94131.60128.9 200306302305273340433020272727247 18 27 32 15 7 12 12 12 170.94 92132.50128.9 END OBSERVED BEGIN F10_PREDICT 20030701 130 129.2 20030702 130 134.1 20030703 140 131.8 . . . 20031027 160 168.8 20031028 165 168.7 20031029 170 168.8 END F10_PREDICT BEGIN AP_PREDICT 20030701 020 20030702 015 20030703 020 . . . 20031027 015 20031028 013 20031029 012 END AP_PREDICT