Corrected Geomagnetic Coordinates

The corrected geomagnetic coordinates were introduced by B.Hultquist and Gustafsson [1960].

For the corrected geomagnetic latitude (CORLAT),co-latitude (CORCOLAT), longitude (CORLON) and local time (CORMLT) calculation the algorithm as follows is used:

• Step 1: The Footprint position calculation by the magnetic field line tracing from the satellite position up to the Ionosphere by using IGRF + Tsyganenko [1987] magnetic field model (the stop trace altitude 110 km).

• Step 2: Tracing back from the Footprint (produced on the Step 1) to the dipole equatorial plane (by using only IGRF magnetic field model up to the geocentric distance 8 RE and dipole field model after this distance).

• Step 3: The CORLON and CORMLT of the original point are equal to the dipole longitude and local time of the point, produced on the step 2.

• Step 4: The CORLAT is found from the equation: (cos CORLAT)**2=1/L. where L (measured in the Earth's Radii Re = 6371.2 km) is the geocentric distance of the point produced on the step 2.
  Corrected geomagnetic co-latitude CORCOLAT is the diference: (90 deg - CORLAT).

References

• Hultquist,B.,and G.Gustafsson, On the magnetic time dependence of auroral zone currents, J.Atmos. Terr.,Phys., 19, 246, 1960
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• The main magnetic field IGRF WWW site http://fdd.gsfc.nasa.gov/IGRF.html
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• Tsyganenko N.A., Global quantitative models of the geomagnetic field in the cislunar magnetosphere for different disturbance levels, Planet.Space Sci., 35, 1347-1358, 1987.
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Dr. Victoria Prokhorenko
vprokhor@iki.rssi.ru

Last updated 08 August 1997