The study of geomagnetism is one of the oldest of the geophysical sciences. Since before the publication of William Gilbert's De Magnete in 1600, people have tried to unravel the mysteries of Earth's magnetic field. 

The National Geophysical Data Center maintains archives of geomagnetic data to further the understanding of Earth magnetism and the Sun-Earth environment. Data at NGDC include surface, ocean, airborne and satellite measurements, as well as models of the main field and its secular change, and models of the Space - Earth environment. Data on Earth's ancient magnetic field are available from archeomagnetic and paleomagnetic measurements. For those interested in learning more about geomagnetism, we have a general information page and a Frequently Asked Questions (FAQ) page.

On-line US Historic Declination (1750-2010) Calculator.
      NGDC 720 degree crustal field model (Sept 2006)

Please feel free to contact us if you have questions on the Earth's Main Field, Space Weather, or Marine Magnetics.

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Calculators | Data | Declination | F A Q
Geomagnetic Observatory Data (SPIDR)
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