EarthRef.org Digital Archive (ERDA) -- NGDC-720 model of the lithospheric magnetic field version 3.1

Description
The NGDC-720 model provides the lithospheric magnetic field vector at any desired location and altitude close to and above the Earth's surface. Anticipated uses are in geological and tectonic studies of the lithosphere, as a local correction for magnetic navigation and heading systems, and the calibration of ground, marine, air- and spaceborne magnetometers. The model was estimated from the EMAG2 Earth Magnetic Anomaly Grid as a degree-719 ellipsoidal harmonic representation of the magnetic potential. Given here are the corresponding spherical harmonic Gauss coefficients to degree and order 740 in the definition commonly used in geomagnetism.

Instructions
This is a text file in free format containing the spherical harmonic coefficients of the lithospheric magnetic field. The user will be required to convert these to a format that is suitable for their preferred geomagnetic field software.