EarthRef.org Digital Archive (ERDA) -- Continuous global geomagnetic field models for the past 3000 years

Description
We present a continuous spherical harmonic model for 1000~BC to 1800~AD, based on a dataset of directional archaeo- and paleomagnetic data and axial dipole constraints. The model, named CALS3K.1, can be used to predict both the field and secular variation. Comparisons and tests with synthetic data lead to the conclusion that CALS3K.1 gives a good general, large-scale representation of the geomagnetic field, but lacks small-scale structure due to the limited resolution of the sparse dataset. The model can be used for comparisons with additional, new data for that time span. For better resolved regions, the agreement of data with CALS3K.1 will provide an idea about the general compatibility of the data with the field and secular variation in that region of the world. For poorly covered regions and time intervals we hope to iteratively improve the model by comparisons with and inclusion of new data. Animations and snapshot plots of model predictions as well as the model coefficients and a FORTRAN code to evaluate them for any time are given here.

Instructions
Download CALS3K_1.zip
It contains the model coefficient files, FORTRAN evaluation code, animations and snapshots plots. The files are described in detail in plain ASCII file readme.txt, which is included in the zipped archive.