Originally constructed in 1995, the Global Oscillation Network Group (GONG) is a network of six identical ground-based solar telescopes distributed around the Earth in order to obtain continuous observations of the Sun. Those sites are located in Big Bear, California (BB); Mauna Loa, Hawaii (ML); Learmonth, Australia (LE); Udaipur, India (UD); El Teide, Spain (TD); and Cerro Tololo, Chile (CT). Additionally, there are three engineering/testbed sites in Boulder, Colorado (TC, TE, and TS). Owned by the National Science Foundation, GONG is operated and maintained by the National Solar Observatory (NSO) with significant funding from NOAA’s Space Weather Prediction Center (SWPC). Each minute, weather permitting, the GONG network observes the Sun at two spectral wavelengths: 676.78nm (a Ni I absorption line) and 656.28nm (the H-alpha absorption line).

Originally constructed in 1995, the Global Oscillation Network Group (GONG) is a network of six identical ground-based solar telescopes distributed around the Earth in order to obtain continuous observations of the Sun. Those sites are located in Big Bear, California (BB); Mauna Loa, Hawaii (ML); Learmonth, Australia (LE); Udaipur, India (UD); El Teide, Spain (TD); and Cerro Tololo, Chile (CT). Additionally, there are three engineering/testbed sites in Boulder, Colorado (TC, TE, and TS). Owned by the National Science Foundation, GONG is operated and maintained by the National Solar Observatory (NSO) with significant funding from NOAA’s Space Weather Prediction Center (SWPC). Each minute, weather permitting, the GONG network observes the Sun at two spectral wavelengths: 676.78nm (a Ni I absorption line) and 656.28nm (the H-alpha absorption line).

Originally constructed in 1995, the Global Oscillation Network Group (GONG) is a network of six identical ground-based solar telescopes distributed around the Earth in order to obtain continuous observations of the Sun. Those sites are located in Big Bear, California (BB); Mauna Loa, Hawaii (ML); Learmonth, Australia (LE); Udaipur, India (UD); El Teide, Spain (TD); and Cerro Tololo, Chile (CT). Additionally, there are three engineering/testbed sites in Boulder, Colorado (TC, TE, and TS). Owned by the National Science Foundation, GONG is operated and maintained by the National Solar Observatory (NSO) with significant funding from NOAA’s Space Weather Prediction Center (SWPC). Each minute, weather permitting, the GONG network observes the Sun at two spectral wavelengths: 676.78nm (a Ni I absorption line) and 656.28nm (the H-alpha absorption line).

This file is comprised of the variation one minute values of the geomagnetic components X, Y and Z. These data were calculated by the Air Force Geophysics Laboratory magnetometer network during the years 1978-1983. The values are variation values and should not be used in looking at absolute values of the geomagnetic components.

This data file consists of Kp indices, Ap indices, Cp indices, C9 indices, sunspot number, and 10.7 cm flux. The most often requested parameter of this file are the Kp indices. These planetary indices are derived from the K indices ( a quasi-logarithmic three-hourly measure of magnetic activity ranging from 0 for the least disturbed periods to 9 for the most disturbed) from 12 observatories located between 46 degrees north geomagneticlatitude and 63 degrees south geomagnetic latitude.

The geomagnetic aa indices are the continuation of the series beginning in the year 1868. A full description of these indices is given in the International Association of Geomagnetism and Aeronomy (IAGA) Bulletin No 33, which contains them for the years 1868-1967. Descriptions are also given (especially comparisons with am, ap, or Ci indices) in two short papers [Ann. Geoph., 27, 62-70, 1971 and J. Geophys. Res., 77, 6870-6874, 1972]. The aa values form 1968-1975 are contained in the IAGA Bulletin 39. From 1976 onward they are included in IAGA Bulletin 32. Revised aa values for the years 1969-1976 have been distributed in 1979 to the recipients of IAGA Bulletin 32 in the form of loose sheets to be inserted in the Bulletin 39 (1968-1975) and 32f (1976). A graph of these values 1868 - 1979 is published in the 426 Part I issue of Solar-Geophysical Data (SGD) (page 137). Revised aa values for 1968-1977 appear in the 411 Part II February 1977 SGD. Briefly, such three-hourly indices as these, computed from K indices of two antipodal observatories (invariant magnetic latitude 50 degrees), provide a quantitative characterization of the magnetic activity, which is homogeneous through the whole series. Half-daily and daily values give an estimation of the activity level very close to that obtained with "am" indices. Values are in gammas and correspond to the activity level at an invariant magnetic latitude of 50 degrees. The aa indices are computed for: N = daily values for the Northern Hemisphere, S = daily values for the Southern Hemisphere, M = half-daily values of aa indices for the Greenwich day. Letters C and K refer to a classification of the quiet days of the month (C = really quiet, K = quiet but with slightly disturbed three-hourly intervals). The letters on the left refer to the 24-hour Greenwich day, on the right to a period of 48 hours centered on the Greenwich noon. The three-hourly indices aa are available from the appropriate World Data Centers in digital form using the format described in IAGA Bulletin 33.

The Geomagnetic Indices Bulletin is a one page sheet containing the magnetic indices Kp, Ap, Cp, An, As, Am and the provisional aa indices. The bulletin is published monthly.

Three orthogonal flux-gate magnetometer elements, (spinning twin fluxgate magnetometer prior to GOES-8) provide magnetic field measurements in three mutually perpendicular components: HP, HE and HN. HP is perpendicular to the satellite's orbital plane. HE lies parallel to the satellite-Earth center line and points earthward. HN is perpendicular to both HP and HE, and points westward for GOES-4 and earlier satellites, and eastward for later spacecraft. The Synchronous Meteorological Satellites (SMS-1 and SMS-2) and the Geostationary Operational Environmental Satellites (GOES-1, GOES-2, etc.) all carry on board the Space Environment Monitor (SEM) instrument subsystem. The SEM has provided magnetometer, energetic particle, and soft X-ray data continuously since July 1974. Geosynchronous satellites have an unobstructed view of the sun for all but the few dozen hours per year when the Earth eclipses the sun. You can identify these intervals as gaps in the X-ray data near satellite local midnight in March-April, and September-October. The volume of these data makes it impossible to issue a guarantee as to the quality of each and every data point. Users should be suspicious of 'spikes' in the data and attempt to correlate them with other sources before assuming that they represent the space environment. The time of these observations has not been corrected for the down-link and preprocessing delay which is within 1 - 5 seconds.

Geomagnetic variation data with 2.5 minute resolution

The geomagnetic aa index provides a long climatology of global geomagnetic activity using 2 antipodal observatories at Greenwich and Melbourne- IAGA Bulletin 37, 1975 p. 128