The Magnetic Field Properties Calculator will computes the estimated values of Earth's magnetic field(declination, inclination, vertical component, northerly component, easterly component, horizontal intensity, or total intensity), for a specific location, elevation and date or range of dates based on the current International Geomagnetic Reference Field (IGRF). The calculated result is a grid that contains the calculated component and the annual change of the component over the geographical area specified. WDeclination is calculated using the current World Magnetic Model (WMM) or International Geomagnetic Reference Field (IGRF) model. While results are typically accurate to 30 minutes of arc, users should be aware that several environmental factors can cause disturbances in the magnetic field.

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 NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) receives the K indices on a current basis from approximately 85 observatories. The K index is a quasi-logarithmic local index of the 3-hourly range in magnetic activity relative to an assumed quiet-day curve for the recording site. First introduced by J. Bartels in 1938, it consists of a single digit 0 through 9 for each 3-hourly interval. The K indices are received on a monthly basis from the various observatories and are available from 1938 to present. The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) also receives KP indices from the Institute for Geophysik in Gottingen, Germany on a monthly basis. The KP index is a planetary index based on the K index from 12 or 13 selected stations and has been derived routinely from 1932.

Geomagnetic 10 second data provides high temporal resolution of geomagnetic variations

The World Magnetic Model High Resolution is a more detailed, accurate depiction of the geomagnetic field than the World Magnetic Model (WMM) because it has more coefficients (18,210 instead of 336) and more digits (4 instead of 1) in each coefficient. The National Geospatial-Intelligence Agency (NGA) highly recommends that all DoD systems use the WMMHR instead of the WMM.

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.

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.

The Enhanced Magnetic Model (EMM) extends to degree and order 720, resolving magnetic anomalies down to 56 km wavelength. The higher resolution of the EMM results in significantly improved pointing accuracy than the World Magnetic Model (WMM), which uses spherical harmonic representation to degree and order 12, resolving the magnetic field at 3000 km wavelength. The EMM model provides the magnetic field vector at any desired location and altitude close to and above the Earth's surface.

The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO) and the International Hydrographic Organization (IHO), for navigation, attitude and heading referencing systems using the geomagnetic field. It is also used widely in civilian navigation and heading systems. The model is produced at 5-year intervals, with the current model expiring on December 31, 2019. The current model WMM2015 is produced jointly by the NGDC and the British Geological Survey (BGS). The model, associated software, and documentation are distributed by NGDC on behalf of US National Geospatial-Intelligence Agency and by BGS on behalf of UK Defence Geographic Centre.