A New Calculation Method for Visual and Digital Geomagnetic Field Model

摘要

In this paper, a new calculation method to establish visual and digital geomagnetic field model is developed with the mapping toolbox of MATLAB. This visual and digital model is built on the 11th generation international geomagnetic reference field (IGRF) model, which is expressed by several complex equations. To acquire the numerical data of geomagnetic field on every place of the earth, the mathematical features of the Schmidt semi-normalized associated Legendre function and the spherical harmonic analysis method are introduced, and a differential method is proposed. Compared with conventional recursive methods, this new calculation method can achieve higher accuracy with less time cost. Furthermore, the software designed with this method can be used to plot the isoline of geomagnetic field within every appointed area. Thus it provides a simple and flexible tool for other researchers.