Historical Magnetic Field

Site Longitude:
Degrees
(Positive for East, Negative for West)
Site Latitude:
 		Degrees
(Positive for North, Negative for South)
Date:

Year (e.g. 1923)
(Negative for BC, positive for AD, 1950 or earlier)

Magnetic Field Declination:
 		Degrees
(Positive for East, Negative for West)
Magnetic Field Inclination:
 		Degrees
(Positive for East, Negative for West)
Magnetic Field Intensity:
 		milliTeslas

Description

Magnetic inclination is the angle through which a freely suspended magnet would dip below the horizon in the magnetic north-south meridional plane. Zero degrees inclination means the magnetic field is parallel to the surface of the earth. Ninety degrees declination means the magnetic field points straight up or down. Declination is ninety degrees at either magnetic pole.

 

The magnetic declination measures the angle between the direction a compass needle points (magnetic north pole) and the direction to the true (geographic) north pole. The magnetic north pole currently is at point in the Northwest Territories, Canada: at about 78.4°N Latitude, and about 104.3°W longitude.

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Instructions

To run the model input a site longitude, site latitude and date (1950 or earlier). Values for latitude and longitude are in degrees and the date is the the 4-digit year. Next, click on the "Run Model" button and the model will return magnetic inclination and declination values, in degrees, along with the field intensity in milliTeslas.

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References

This computer code for this model is based on CALS7Kfield.f and its associated data file CALS7K.2. We are grateful to the researchers who did this work and gave permission to adapt their computer code to a web browser.

  • Korte, M., A. Genevey, C. G. Constable, U. Frank, and E. Schnepp (2005), Continuous geomagnetic field models for the past 7 millennia: 1. A new global data compilation, Geochem. Geophys. Geosyst., 6, Q02H15, doi:10.1029/2004GC000800.
  • Korte, M., and C. G. Constable (2005), Continuous geomagnetic field models for the past 7 millennia: 2. CALS7K, Geochem. Geophys. Geosyst., 6, Q02H16, doi:10.1029/2004GC000801.

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