The note discusses the differences between two Polar Cap South (PCS) index series both submitted from Arctic and Antarctic Research Institute (AARI) , St. Petersburg, Russia,. One PCS series is published via the AARI web portal https://pcindex.org while the other PCS series is distributed via the web portal http://isgi.unistra.fr of the International Service for Geomagnetic indices (ISGI). Both PCS series have been downloaded on 23 December 2021 for the comparisons. In principle, the two series should be identical. However, differences on the order of magnetic storm amplitude (>3 mV/m) have been detected and are reported in the present note.
Steps to reproduce
On 23 December 2021, Polar Cap South (PCS) indices generated at the Arctic and Antarctic Research Institute (AARI) in St. Petersburg were downloaded from two different sources, the AARI web https://pcindex.org and the web portal http://isgi.unistra.fr for the International Service for Geomagnetic indices (ISGI). The two PCS index series should, in principle, present the same index values. However differences between the values of the two PCS series on the order of magnetic storm amplitude (>3 mV/m) were detected. From previous investigations reported, among others, by Stauning (2018, 2020, and 2021) the PCS series submitted from AARI was found being invalid, which the present note has confirmed. The validity of the other series could not be confirmed. Ample references are provided in the note.