North–South Asymmetry in Solar Activity and Solar Cycle Prediction, IV: Prediction for Lengths of Upcoming Solar Cycles. (arXiv:1904.11500v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Javaraiah_J/0/1/0/all/0/1">J. Javaraiah</a>
We analyzed the daily sunspot-group data reported by the Greenwich
Photoheliographic Results (GPR) during the period 1874-1976 and Debrecen
Photoheliographic Data (DPD) during the period 1977-2017 and studied
North-South asymmetry in the maxima and minima of the Solar Cycles 12-24. We
derived the time series of the 13-month smoothed monthly mean corrected
whole-spot areas of the sunspot groups in the Sun’s whole sphere (WSGA),
northern hemisphere (NSGA), and southern hemisphere (SSGA). From these smoothed
time series we obtained the values of the maxima and minima, and the
corresponding epochs, of the WSGA, NSGA, and SSGA Cycles 12-24. We find that
there exists a 44-66 years periodicity in the North-South asymmetry of the
minimum. A long periodicity (130-140 years) may exist in the asymmetry of the
maximum. A statistically significant correlation exists between the maximum of
SSGA Cycle n and the rise time of WSGA Cycle n + 2. A reasonably significant
correlation also exists between the maximum of WSGA Cycle n and the decline
time of WSGA Cycle n + 2. These relations suggest that the solar dynamo carries
memory over at least three solar cycles. Using these relations we obtained the
values 11.7 + or – 0.15 years, 11.2 + or – 0.2 years, and 11.45 + or – 0.3
years for the lengths of WSGA Cycles 24, 25, and 26, respectively, and hence,
July 2020, October 2031, and March 2043 for the minimum epochs (start dates) of
WSGA Cycles 25, 26, and 27, respectively. We also obtained May 2025 and March
2036 for the maximum epochs of WSGA Cycles 25 and 26, respectively. It seems
during the late Maunder minimum sunspot activity was absent around the epochs
of the maxima of the NSGA-cycles and the minima of the SSGA-cycles, and some
activity was present at the epochs of the maxima of some SSGA-cycles and the
minima of some NSGA-cycles.
We analyzed the daily sunspot-group data reported by the Greenwich
Photoheliographic Results (GPR) during the period 1874-1976 and Debrecen
Photoheliographic Data (DPD) during the period 1977-2017 and studied
North-South asymmetry in the maxima and minima of the Solar Cycles 12-24. We
derived the time series of the 13-month smoothed monthly mean corrected
whole-spot areas of the sunspot groups in the Sun’s whole sphere (WSGA),
northern hemisphere (NSGA), and southern hemisphere (SSGA). From these smoothed
time series we obtained the values of the maxima and minima, and the
corresponding epochs, of the WSGA, NSGA, and SSGA Cycles 12-24. We find that
there exists a 44-66 years periodicity in the North-South asymmetry of the
minimum. A long periodicity (130-140 years) may exist in the asymmetry of the
maximum. A statistically significant correlation exists between the maximum of
SSGA Cycle n and the rise time of WSGA Cycle n + 2. A reasonably significant
correlation also exists between the maximum of WSGA Cycle n and the decline
time of WSGA Cycle n + 2. These relations suggest that the solar dynamo carries
memory over at least three solar cycles. Using these relations we obtained the
values 11.7 + or – 0.15 years, 11.2 + or – 0.2 years, and 11.45 + or – 0.3
years for the lengths of WSGA Cycles 24, 25, and 26, respectively, and hence,
July 2020, October 2031, and March 2043 for the minimum epochs (start dates) of
WSGA Cycles 25, 26, and 27, respectively. We also obtained May 2025 and March
2036 for the maximum epochs of WSGA Cycles 25 and 26, respectively. It seems
during the late Maunder minimum sunspot activity was absent around the epochs
of the maxima of the NSGA-cycles and the minima of the SSGA-cycles, and some
activity was present at the epochs of the maxima of some SSGA-cycles and the
minima of some NSGA-cycles.
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