Indices of Geomagnetic Activity
Geomagnetic Indices
Geomagnetic indices have been developed to characterise the variability of the Earth's magnetic field, in all its complexity, in a single number. There are many such indices that each characterise a different aspect or time-frame of the dynamic geomagnetic field. The most widely used of these is the K index, a quasi-logarithmic index of geomagnetic activity relative to an estimated undisturbed or regular quiet day variation for the recording site. Links to sites with other magnetic indices and information can be accessed from other tabs on this page.
k index
The k index is a quasilogarithmic index of geomagnetic activity relative to an assumed quiet day curve for the recording site. k is a code from 0-9 that characterizes magnetic activity (0 being the least active field and 9 the most active field) over a 3 hour period.
k indices from Canberra, Gnangara, Gingin and Mawson observatories are available online.
Index availability:
01-JAN-1980 to for Canberra Geomagnetic Observatory.
01-JAN-1995 to for Gnangara Geomagnetic Observatory (superseded by Gingin).
01-AUG-2010 to for Gingin Geomagnetic Observatory.
01-JAN-2005 to for Mawson Geomagnetic Observatory.