Geomagnetic 10 second data provides high temporal resolution of geomagnetic variations

The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) receives, on a monthly basis, Q indices from Sodankyla. These data are available from July 1957 to the present. Sodankyla indices are the most complete records of Q indices that NCEI has. The archive also contains Q indices from 15 other observatories. The Q index is a measure of geomagnetic activity assigned by high latitude (geomagnetic latitude > 58 degrees) geomagnetic observatories for each 15 minute interval. The index is designed to study auroral and ionospheric phenomena over a time scale smaller than that possible with KP. The Q scale is loosely logarithmic, with possible values from 0 to 11.

This file is comprised of absolute mean hourly values of the geomagnetic components D, H and Z or X, Y and Z. These values, on magnetic tape, are available from approximately 220 of the 400 worldwide observatories which have ever operated. Most of the values were hand-scaled from the analog recordings (magnetograms) and were added to the file via punched cards. From some observations, for more recent years, there are means of values recorded directly on magnetic tape from digital magnetometers at various sample rates, for example, each minute. The accuracy of these data varies but is generally good, particularly for the more recent years. Approximately 60 observation-years of these data are added to the files each year.

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.

1 minute and hourly values reported as definitive from Intermagnet observatories.

The abbreviations used for observatory names are as follows: GEOMAGNETIC OBSERVATORIES Code Station Geomagnetic Latitude ABG Alibag AMS Martin de Vivie. These data present the principal magnetic storms for the month as reported by several observatories through cooperation with the International Association of Geomagnetism and Aeronomy (IAGA). These are the data formerly published in the Journal of Geophysical Research. They are now, however, grouped by the storm rather than by station. The geomagnetic latitude of the station is indicated. The beginning time is given to the hour and minute in UT. The tupe of sudden commencement, if any, together with its magnitude in each element D, H or Z is next in the format: sc = sudden commencement; sc* = small initial impulse followed by main impulse (in this case the amplitude is that of the main pulse only, neglecting the initial brief pulse); dots in these columns represent a stomr with gradual commencement; blanks indicate no data entries. Signs of amplitudes of D and Z are taken albegraically; D reckoned positive if toward the east and Z reckoned positive if vertically downward. In the next columns the day and the three-hour periods on that day when the K index reached its maximum are given followed by the K index value. In the next three columns the maximum ranges in D, H and Z during the storm are given. The ending time is given only to the nearest hour. This is the time of cessation of reasonably marked disturbance movements in the trace. More specifically, it is the time when the K index measure has diminished to 2 or less for a reasonable period. For each date the data are listed in north-to-south geomagnetic latitude order.

This data file is comprised of instantaneous values of the geomagnetic components D, H, and Z or X, Y, and Z at 2.5-minute intervals. These values were derived from analog recordings (magnetograms) with the aid of semi-automatic digitizing equipment from a worldwide network of about 75 observatories.

Report on the status of world wide geomagnetic observatories

The High Definition Geomagnetic Model (HDGM) is a global, high resolution model of the Earth's geomagnetic main and crustal field, providing magnetic field values (total field, dip, and declination) at any point above or below the Earth's surface. Well planners can use HDGM to compute magnetic reference values at any point, as well as easily integrate HDGM into their directional drilling software. HDGM is updated annually to correctly model secular changes in the geomagnetic field.

The High Definition Geomagnetic Model (HDGM) is a global, high resolution model of the Earth's geomagnetic main and crustal field, providing magnetic field values (total field, dip, and declination) at any point above or below the Earth's surface. Well planners can use HDGM to compute magnetic reference values at any point, as well as easily integrate HDGM into their directional drilling software. HDGM is updated annually to correctly model secular changes in the geomagnetic field.