 |
| Titel |
Predicting amplitude of solar cycle 24 based on a new precursor method |
| VerfasserIn |
A. Yoshida, H. Yamagishi |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 28, no. 2 ; Nr. 28, no. 2 (2010-02-08), S.417-425 |
| Datensatznummer |
250016773
|
| Publikation (Nr.) |
 copernicus.org/angeo-28-417-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| It is shown that the monthly smoothed sunspot number (SSN) or its rate of
decrease during the final years of a solar cycle is correlated with the
amplitude of the succeeding cycle. Based on this relationship, the amplitude
of solar cycle 24 is predicted to be 84.5±23.9, assuming that the
monthly smoothed SSN reached its minimum in December 2008. It is further
shown that the monthly SSN in the three-year period from 2006 through 2008
is well correlated with the monthly average of the intensity of the
interplanetary magnetic field (IMF). This correlation indicates that the SSN
in the final years of a solar cycle is a good proxy for the IMF, which is
understood to reflect the magnetic field in the corona of the sun, and the
IMF is expected to be smallest at the solar minimum. We believe that this
finding illuminates a physical meaning underlying the well-known precursor
method for forecasting the amplitude of the next solar cycle using the aa
index at the solar minimum or its average value in the decaying phase of the
solar cycle (e.g. Ohl, 1966), since it is known that the geomagnetic
disturbance depends strongly on the intensity of the IMF. That is, the old
empirical method is considered to be based on the fact that the intensity of
the coronal magnetic field decreases in the late phase of a solar cycle in
parallel with the SSN. It seems that the precursor method proposed by
Schatten et al. (1978) and Svalgaard et al. (2005), which uses the intensity
of the polar magnetic field of the sun several years before a solar minimum,
is also based on the same physical phenomenon, but seen from a different
angle. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|