These data are vector and scalar component values of the Earth's magnetic field for 2004 recorded at the Boulder Magnetic Observatory in Colorado. Vector values are measured using 3 mutually orthogonal fluxgate magnetometer sensors. The scalar value of the total magnetic field is recorded with a proton precession magnetometer. All values are calibrated with measurements of the absolute value of the geomagnetic field using a DI-Flux magnetometer. The data are numerically filtered to prevent aliasing, and quality controlled during processing. Longer period values of the field, including hourly, daily, monthly, and annual means are derived from the 1-minute data.

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.

Information on the past and present orientation of the Earth's magnetic field is available from the National Geophysical Data Center (NGDC) which serves as the national data bank for geomagnetic data. The Earth's magnetic field has been measured by land surveys, ships, aircraft and satellites at hundreds of locations resulting in millions of observations. Many of the observations are of poor quality or are unevenly distributed around the globe. Because of these limiting factors and the variation of the main magnetic field with time, the Earth's field is usually approximated by mathematical models. These models, adjusted to fit selected available observations, have wide application in geophysical and space sciences. Surveyors can obtain data and information for individual specific locations worldwide. Past values of the magnetic field are available from models for areas within the conterminous U.S. from 1750 or from 1945 worldwide. These mathematical models must be periodically updated due to the changing nature of the Earth's magnetic field. NGDC maintains the models and data base of observations to track secular variation of the Earth's magnetic field. Models and software are available on-line. The global geomagnetic observations data bases for secular change studies include high-quality magnetic observations made at observatories worldwide since 1800. Other geomagnetic data bases are: IAGA Repeat Station data base which contains observations from exact reoccupations, Other land Surveys containing miscellaneous land observations worldwide since 1800 including a few thousand observations made at sea by the non-magnetic ships, Carnegie and Zarya, Vector airborne surveys from the Project Magnetic aircraft, satellite and selected marine observations. Most of the surface data are available on-line. At most locations, three magnetic elements were observed: Either declination (D), Inclination (I), and horizontal intensity (H), or declination, horizontal intensity, and vertical intensity (Z), or total intensity (F). Where possible, the values for other magnetic elements, usually the north component (X) and east component (Y), were derived by the computer. The altitude, latitude, and longitude are recorded for each observation. The observatory annual means file contains the results of more of the observatories operating since 1800. Files are revised as new data become available. Searches and plots of data from selected stations can be made. These secular change files are the principal source for tracking the long-period changes in the direction and intensity of the Earth's magnetic field. Other data include a digital bibliography of historical magnetic survey publications at NGDC and the co-located World Data Center-A. Over 750 reports published from the 1830's to 1980's were inventoried in a digital bibliography and digitally imaged in .PCX format. The digital images of these reports have been written to magnetic tape.

The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) receive airborne magnetic survey data from US and non-US agencies. In an effort to provide a central library for digital aeromagnetic data in the public domain, NCEI is continuing to assimilate new digital data from aeromagnetic surveys in the United States. Major contributors to this important data base include the U.S. Geological Survey, U.S. Naval Oceanographic Office, U.S. Naval Research Laboratory, Woods Hole Oceanographic Institution, the University of Texas, and the Natural Resources Canada (NRCAN). The details of these surveys are contained in an automated inventory system Geophysical Data System (GEODAS). The philosophy of exchange of data from the archive for new contributions has stimulated many organizations to transfer their data holdings to the Data Center.

Report on the status of world wide geomagnetic 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.

Geomagnetic variation data with 2.5 minute resolution

Geomagnetic 10 second data provides high temporal resolution of geomagnetic variations

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.