Latitude, Geomagnetic

the angle ϕ, which is the complement (to 90°) of the angle formed by the axis of a uniformly magnetized earth (the axis of the earth’s magnetic dipole) and a radius vector drawn from the center of the earth to a given point on its surface. Geomagnetic latitude ranges from +90° at the geomagnetic pole in the northern hemisphere to –90° at the pole in the southern hemisphere.

The concept of geomagnetic latitude is used in studying various geophysical phenomena. However, for detailed investigations of the latitudinal distribution of the aurora borealis, magnetic and ionospheric disturbances, the absorption of cosmic radiation, and similar phenomena, the concept of corrected geomagnetic latitude is used. Its calculation considers both the dipole members and the higher terms in the expansion of the earth’s potential in a series of spherical harmonics. (SeeTERRESTRIAL MAGNETISM.)