Table 1

Main characteristics of scaling conditions for frequently used PC index versions.

Version Epoch for scaling Solar activity Reverse convection Reference level
OMNI 1977–1980 Peak of cycle Frequent No QDC, BL only
AARI 1998–2001 Peak of cycle Frequent BL and QDC*
IAGA 1997–2009 Cycle average Average BL and QDC**
DMI 1997–2009 Cycle average Excluded BL and QDC***

QDC: Based on running 30 days quiet samples (Janzhura and Troshichev, 2008).


QDC: Running 30 days quiet samples + solar wind sector contribution (Janzhura and Troshichev, 2011).


QDC: 40 days solar rotation weighted quiet samples (Stauning, 2011).

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