Geomagnetic Polar Cap (PC) Index

Report UAG-103, or available on Diskette

The PC-index is a fifteen-minute index for magnetic activity in the (P)olar (C)ap. It is based on data from a single nearpole station, and aimed to monitor the polar cap magnetic activity generated by such solar wind parameters as the southward component of the interplanetary magnetic field (IMF), the azimuthal component of the IMF (By), and the solar wind velocity (v). The station Thule, located in the village Qaanaaq in Greenland at 86.5° geomagnetic invariant latitude, fulfills the requirement of being close to the magnetic pole in the northern hemisphere. The station Vostok at 83.3° does the same in the southern hemisphere. The PC index is derived independently for these two stations.

The PC-index is based on an idea by Troshichev et al. (1979) and developed in papers by Troshichev and Andresen (1985), Vennerstrom and Friis-Christensen (1989), Troshichev et al. (1988), Vennerstrom (1991), and Vennerstrom et al. (1991). Earlier data for 1975 through 1982 appear in Troshichev et al. (1991). The data from 1975 to 1993 are published in Report UAG-103 in graphical form. These data are published monthly in Solar-Geophysical Data.

This is a plot of the Thule PC-index for the massive geomagnetic storm of March 1989.

The data are available online or in a printed UAG Report. Data are present for the following years: Thule, 1975-2006, and Vostok, 1978-1979, 1983-1999. To find out more information about ordering, click here.

We also have a listing of all the available UAG Reports. To see this list, click here.