Spline Models

The Spline Model is a continuous representation of the main geomagnetic field for the time period 1900-1995. The model is composed of a degree and order 13 spherical harmonic expansion to represent the Earth's main magnetic field from internal sources and a degree 1 expansion for the external sources. The secular variation of the main field is represented by cubic B-splines.

Main field models are available by anonymous ftp from the Geomagnetism Group at NASA-Goddard Space Flight Center.

mevalu.f (51 Kb),

Fortran subroutine for evaluating GSFC spline-type models. The subroutine documentation is self-explanatory. The only code modification required is that the path to the model file in the "open" statement reflect your environment, i.e. change:

OPEN(UMDL,FILE='~sabaka/umdl.gsfcs95-sc')

to:

OPEN(UMDL,FILE='your path for model file')

umdl.gsfcs95-sc.gz (53 kb)

The complete GSFC(S95-sc) model. This model is described in detail in the paper: "The Geomagnetic Field 1900-1995, Including the Large-Scale Field from Magnetospheric Sources, and the NASA Candidate Models for the 1995 Revision of the IGRF", T.J. Sabaka, R.A. Langel, R.T. Baldwin, and J.A. Conrad, in press for a special issue JGG, 1996.

Abstract

umdl.gsfcs95-sc.external-only.gz

The external field portion of the GSFC(S95-sc) model.

Any questions may be directed to:

Terry Sabaka

Phone : 301-286-4865

Email : sabaka@geomag.gsfc.nasa.gov

Building/Office : 22/163

Mailing Address : NASA/GSFC, Code 921, Greenbelt, MD 20771

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