Kp and Dst index

The Dst index describes the earth magnetic activity. A earth magnetic storm is defined as a change in Dst. The magnitude of the storm is classified as: moderate (-50 nT> minimum of Dst <-100 nT), intensive (-100 nT> minimum of Dst <-250 nT) or superstorm (minimum of Dst> -250 nT). From IRF-Lund

Kp is the global earth magnetic storm index. The Kp index has a scale of 0 to 9, where a value of 0 means very little earth magnetic activity and a value of 9 means an extreme earth magnetic storm. From IRF-Lund

Earth magnetic field variations