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Transpolar convection and magnetospheric ring current relations: real time applications of the Polar Cap (PC) indices
  • Peter Stauning
Peter Stauning
Danish Meteorological Institute

Corresponding Author:pst@dmi.dk

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The relations between transpolar plasma convection intensities recorded by the Polar Cap (PC) indices and magnetospheric ring current intensities recorded by the asymmetric ASY-H indices and the symmetric Dst and SYM-H indices are examined. The present work believed to be the first of its kind examines the validity of previously derived relations between polar cap and ring current indices when used in real time applications. Polar cap (PC) indices are here derived in simulated real-time versions by using past data only from -40 days up to current time in the construction of the quiet reference levels (QDCs) for the magnetic data. From analyses spanning a decade (2009-2018), equivalent ASY-H index values were derived from a linear relation with simulated real-time PCN (North) and PCS (South) indices combined to form the non-negative PCC indices. For cases of strong magnetic storms (Dst(peak)<-100 nT, the equivalent ASY-H indices were found to agree well with reported (real) ASY-H index values. The simulated real-time PCC indices, furthermore, have been used in a PC-based source function to derive equivalent values of the total ring current indices Dst (or SYM-H) up to one hour ahead of time. With integration of the source function throughout a decade (2009-2018) with no attachment to reported Dst values, the simulated real-time equivalent Dst indices displayed close agreement with real Dst index values. The applied method could be used without modifications to generate PC index values and derived ASY-H and Dst (or SYM-H) index values in real-time space weather applications.
Jul 2021Published in Space Weather volume 19 issue 7. 10.1029/2020SW002702