| The NOAA National Centers for Environmental Information (formerly National Geophysical
Data Center) receives on a monthly basis, the KM, KN, KS indices from Institue De
Physique Du Globe, Paris, France. These data are available from 1959 to present. The
KN and KS are planetary indices which have been derived using data obtained by northern
and southern hemisphere observatories, respectively. KM is mean value and is usually
very close in magnitude to KP. These indices reflect the geomagnetic activity occurring
in the Earth?s northern and southern hemispheres. |