igrf11magm - Calculate Earth's magnetic field using 11th generation of International Geomagnetic Reference Field

Syntax

Description

[mag_field_vector, hor_intensity, declination, inclination, total_intensity, mag_field_sec_variation, sec_variation_horizontal, sec_variation_declination, sec_variation_inclination, sec_variation_total] = igrf11magm(height, latitude, longitude, decimal_year) calculates the Earth's magnetic field and the secular variation at a specific location and time. This function uses the 11th generation of the International Geomagnetic Reference Field (IGRF-11).

Tips

• The igrf11magm function is valid between the heights of –1000 meters to 600000 meters.

• The igrf11magm function is valid between the years of 1900 and 2015.

• This function has the limitations of the International Geomagnetic Reference Field (IGRF).

Input Arguments

height	Scalar distance, in meters, from the surface of the Earth.
latitude	Scalar geodetic latitude, in degrees. North latitude is positive, south latitude is negative.
longitude	Scalar geodetic longitude, in degrees. East longitude is positive, west longitude is negative.
decimal_year	Scalar year, in decimal format. This value is the desired year to include any fraction of the year that has already passed.

Output Arguments

mag_field_vector	Magnetic field vector, in nanotesla (nT). Z is the vertical component (+ve down).
hor_intensity	Horizontal intensity, in nanotesla (nT).
declination	Declination, in degrees (+ve east).
inclination	Inclination, in degrees (+ve down).
total_intensity	Total intensity, in nanotesla (nT).
mag_field_sec_variation	Secular variation in magnetic field vector, in nT/year. Z is the vertical component (+ve down).
sec_variation_horizontal	Secular variation in horizontal intensity, in nT/year.
sec_variation_declination	Secular variation in declination, in minutes/year (+ve east).
sec_variation_inclination	Secular variation in inclination, in minutes/year (+ve down).
sec_variation_total	Secular variation in total intensity, in nT/year.

Examples

Calculate the magnetic model 1000 meters over Natick, Massachusetts on July 4, 2005 using IGRF-11:

[XYZ, H, DEC, DIP, F] = igrf11magm(1000, 42.283, -71.35, ...
decyear(2005,7,4))

XYZ =

  1.0e+004 *

    1.8982   -0.5176    4.9558

H =

  1.9675e+004

DEC =

  -15.2524

DIP =

   68.3467

F =

  5.3320e+004

References

Lowes, F. J. "The International Geomagnetic Reference Field: A 'Health' Warning." January, 2010. http://www.ngdc.noaa.gov/IAGA/vmod/igrfhw.html

Blakely, R. J. Potential Theory in Gravity & Magnetic Applications, Cambridge, UK: Cambridge University Press, 1996.

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