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Geomagnetic Models and SoftwareNGDC-720: September 2006 release of version 1.0 crustal magnetic field model. A convenient way of representing geomagnetic fields is to expand the scalar magnetic potential into spherical harmonic functions that can then be evaluated at any desired location to provide the magnetic field vector, its direction, or the anomaly of the total intensity of the field. The NGDC-720 model provides such an expansion for the crustal field from spherical harmonic degree 16 to 720, corresponding to the waveband of 2500 km to 56 km. The degree 720 cut-off corresponds to an angular wavelength of 30 arc minutes, providing a 15 arc minute model resolution. Revised on-line calculators for the IGRF (1900-2010), DoD WMM (2005-2010), Declination only (1900-2010), US Historic Declination (1750-2010) IAGA Web Image Spreadsheet Tool - display and download IAGA magnetic field maps and data from 1900 - 2005. The Wist allows the user to select the number of rows (years) and columns (magnetic elements) to display. Each "cell" of the Wist displays the appropriate map for the selected year and element and links to the PDF for a higher resolution version of the map and to the data used to create the map. The Epoch 2005-2010 Models
Note: To learn more about these models, visit the home Web sites for the US / UK World Magnetic Model (WMM) 2005 and IAGA IGRF-10 . NGDC distributes two main magnetic field models, the International Association of Geomagnetism and Aeronomy (IAGA) International Geomagnetic Reference Field (IGRF) model and the Department of Defense (DoD) World Magnetic Model (WMM). You can download the models for use on your own machine, or compute magnetic field values online from the current IGRF model. Before using the IGRF please look at the 'Health Warning'. |
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