EarthRef.org Digital Archive (ERDA) -- Holocene geomagnetic field model CALS10k.1b

Description
We present a continuous global geomagnetic field model for the past 10 millennia: CALS10k.1b, covering the time span from 8000 BC to 1990AD. The model was determined by regularized least squares inversion of archeo- and paleomagnetic data using spherical harmonics in space and cubic B-splines in time. It is the average of 2000 models where data and ages where varied according to uncertainty estimates in a bootstrap approach. Model uncertainties in the form of one standard deviations on the coefficients as obtained from the averaging are provided. The model is considered to be a robust low resolution representation of Holocene field evolution.
Model coefficients and Fortran evaluation code are provided here.

Instructions
Download and unzip the material. File CALS10k.1b is the model coefficient file which is read in by the Fortran programs. It has to be in the same directory. File CALS10kfield.f is Fortran source code for a program to provide time series of declination, inclination and intensity together with uncertainty estimates for any location on Earth's surface, which is requested as latitude and longitude. File CALS10kcoefs.f is Fortran source code for a program to provide spherical harmonic model coefficients with uncertainty estimates for a fixed point in time, which is requested as input. See top of the file for description of output file.