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Different contributions to space weather and space climate from different big solar active regions
The purpose of this paper is to show that large active regions (ARs) with
different magnetic configurations have different contributions to short-term
and long-term variations of the Sun. As a case study, the complex -type
AR 12673 and the simple -type AR 12674 are investigated in detail. Since
the axial dipole moment at cycle minimum determines the amplitude of the
subsequent cycle and space climate, we have assimilated the individual observed
magnetic configurations of these two ARs into a surface flux transport model to
compare their contributions to the axial dipole moment . We find that AR
12673 has a significant effect on at the end of the cycle, making it weaker
because of the abnormal and complicated magnetic polarities. An initial
strongly positive ends up with a strongly negative value. The flare-poor AR
12674 has a greater contribution to the long-term axial dipole moment than the
flare-rich AR 12673. We then carry out a statistical analysis of ARs larger
than 800 Hem from 1976 to 2017. We use the flare index FI and define an
axial dipole moment index DI to quantify the effects of each AR on space
weather and space climate, respectively. Whereas the FI has a strong dependence
on the magnetic configuration, the DI shows no such dependence. The DI is
mainly determined by the latitudinal location and the latitudinal separation of
the positive and negative magnetic fluxes of the ARs. Simple ARs have the same
possibility as complex ARs to produce big DI values affecting space climate.Comment: 18 pages, 8 figures, Accepted for publication in the Astrophysical
Journa
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