CALS3k.4 and CALS3k.4b

Global geomagnetic field reconstructions on millennial time scales can be based on comprehensive paleomagnetic data compilations but, especially for older data, these still suffer from limitations in data quality and age controls as well as poor temporal and spatial coverage. Here we present updated global models for the time interval 0 - 3 ka where additions to the data basis mainly impact the South-East Asian, Alaskan, and Siberian regions. Bootstrap experiments to generate uncertainty estimates for the model take account of uncertainties in both age and magnetic elements and additionally assess the impact of  sampling in both time and space. Based on averaged results from bootstrap experiments, taking account of data and age uncertainties, we distinguish more conservative model estimates CALS3k.nb representing robust field structure at the core–mantle boundary from relatively high resolution models CALS3k.n for model versions n = 3 and 4. We presently consider CALS3k.4 the best high resolution model and recommend the more conservative lower resolution version for studies of field evolution at the CMB.

Reference:  

  • Korte, M. and C. Constable (2011): Improving geomagnetic field reconstructions for 0 - 3ka. Phys. Earth Planet. Int., 188, 247-259

Radial field component (Br) at the core-mantle-boundary


Download

FileTypeSizeDateContent
cals3k-4.zip ZIP2.7MBNov. 2011Four ASCII files with coefficients: CALS3k.4, CALS3k.4b, CALS3k.3, CALS3k.3b. Fortran source code fieldpred3k.f to produces time series of declination, inclination and intensity for any location on the Earth's surface from any of the four models, and fielduncert3k.f to produces time series with uncertainty estimates based on the bootstrap from models CALS3k.4b or CALS3k.3b.
CALS3k-4anim.zipZIP3.9MBNov. 2011Animations of radial field component (Br) at the core-mantle-boundary as predicted by the four models and of the radial field differences between model versions 3 and 4.

Contact

Profile photo of  Dr. Monika Korte

Dr. Monika Korte
Geomagnetism

Behlertstraße 3a
Building K 3, room 116
14467 Potsdam
tel. +49 331 288-1268