Copyright © Klaus Piontzik  
German Version 
The quantitative numeric Fourier analysis of the earth's magnetic field (IGRF 1984)
yields the following result for the magnetic flux density at the earth's surface:
4.5.2.1  Equation: 
The evaluation provides all three kinds of spherical harmonics,
so zonal, sectoral and tesseral forms, as well as a static part.
The zonal and sectoral part of the spherical harmonics can be grasped to one grid, called the grid ZS. This behaves then like a tesseral spherical harmonic, so as a grid. 
4.5.2.2 Equation:  grid ZS =
zonal + sectoral B_{ZS} = B_{z }+ B_{S} 
Then the entire magnetic field can be represented like this: 
4.5.2.3  Equation:  B_{total } = B_{static }+ B_{ZS }+ B_{tesseral} 
Comment: In the equation 4.5.2.1 exist 17 intensity values that lie between one and eleven Mikrotesla liegen. All All other values are in the range of nanoTesla!!! 
200 sides, 23 of them in color 154 pictures 38 tables Production und Publishing: ISBN 9783735738547 Price: 25 Euro 
