Articles | Volume 36, issue 2
Ann. Geophys., 36, 621–631, 2018
Ann. Geophys., 36, 621–631, 2018

Regular paper 16 Apr 2018

Regular paper | 16 Apr 2018

A critical note on the IAGA-endorsed Polar Cap (PC) indices: excessive excursions in the real-time index values

Peter Stauning

Data sets

Polar Cap (PC) Index O. A. Troshichev

Short summary
The Polar Cap (PC) indices, PCN (North) based on magnetic data from Qaanaaq (Thule) and PCS (South) based on Vostok data, reflect the transpolar convection of plasma and magnetic fields. The PC indices could be used, among others, to indicate the energy transfer from the solar wind to the magnetosphere–ionosphere–thermosphere system in space weather monitoring applications. The present IAGA-endorsed methods to derive PC indices in real time are found to generate inconsistent index values.