*Definitive PCS data are presented for the period 1998-2018.
Recalculation of 'definitive PCS index' was carried out in agreement with document “Restructuring and harmonizing the code used to calculate the Definitive Polar Cap Index” [Nielsen and Willer, 2019]. The quality of the magnetic data obtained at Vostok station in 1998-2018 was checked preliminary, and the necessary corrections in the data series used for the PCS index derivation were made.
