North-South Asymmetry of Some Solar Parameters: A study Based on The Dominance of Hemispheric Sunspot Activity During the Solar Cycles 18–24

2021 ◽  
Author(s):  
M.A. El-Borie ◽  
A.M. El-Taher ◽  
A.A. Thabet ◽  
S.F. Ibrahim ◽  
A.A. Bishara
Keyword(s):  
Sunspot Activity ◽  
Solar Cycles ◽  
South Asymmetry

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
Vol 7 (4) ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

Solar Activity Changes During Prolonged Sunspot Minima as Inferred from Indian Monsoon Rainfall Variations

2018 ◽  
Vol 13 (S340) ◽  
pp. 209-210
Author(s):  
S. Ambily ◽  
V. G. Haritha ◽  
C. Sunil Kumar Morais ◽  
T. E. Girish
Keyword(s):  
Solar Activity ◽  
Monsoon Rainfall ◽  
Indian Monsoon ◽  
Maunder Minimum ◽  
Sunspot Activity ◽  
Indian Monsoon Rainfall ◽  
Quadrupole Field ◽  
Rainfall Variations ◽  
Extreme North ◽  
South Asymmetry

AbstractWe could find a new 5 year periodicity in the occurrences of peaks in sunspot activity and inferred deviations of annual Indian monsoon rainfall variations from the normal during the Maunder minimum (MM) period. This result is explained in terms of solar dynamo functioning in a different mode from normal during the MM where quadrupole field (first harmonic, 5-5.5 years) dominate over dipole field (fundamental, 11 years) causing extreme north south asymmetry in sunspot activity.

scholarly journals The Main Component Analysis of the Longitudinal Distribution of Solar Activity

1991 ◽  
Vol 130 ◽  
pp. 275-276
Author(s):  
Ladislav Hejna ◽  
Hubertus Wöhl
Keyword(s):  
Time Series ◽  
Solar Activity ◽  
Sunspot Group ◽  
Component Analysis ◽  
Longitudinal Distribution ◽  
Sunspot Activity ◽  
Significant Feature ◽  
Solar Cycles ◽  
Main Component Analysis ◽  
Main Component

Abstract In this contribution, preliminary results of the main component analysis of Bartels diagram of time series of daily values of sunspot group numbers for solar cycles 18, 19 and 20 are presented. The results obtained suggest that the most significant feature in the longitudinal distribution of sunspot activity is the existence of preferred solar hemispheres alternating with a mean period of 2.5 Bartels rotations.

scholarly journals Can the long-term hemispheric asymmetry of solar activity result from fluctuations in dynamo parameters?

2019 ◽  
Vol 625 ◽  
pp. A37 ◽  
Author(s):  
Alexander Nepomnyashchikh ◽  
Sudip Mandal ◽  
Dipankar Banerjee ◽  
Leonid Kitchatinov
Keyword(s):  
Hemispheric Asymmetry ◽  
Dynamo Model ◽  
Sunspot Activity ◽  
Regular Component ◽  
Symmetric Part ◽  
Solar Cycles ◽  
Dynamo Mechanism ◽  
Magnetic Cycles ◽  
Polar Magnetic Fields

Context. The hemispheric asymmetry of sunspot activity observed possesses a regular component varying on a timescale of several solar cycles whose origin and properties are currently debated. Aims This paper addresses the question of whether the long-term hemispheric asymmetry can result from random variations of solar dynamo parameters in time and latitude. Methods. Scatter in the observed tilt angles of sunspot groups was estimated to infer constraints on fluctuations in the dynamo mechanism for poloidal field regeneration. A dynamo model with fluctuations in the Babcock-Leighton type α-effect was designed in accordance with these constraints and then used to compute a large number of magnetic cycles for statistical analyses of their hemispheric asymmetry. Results Hemispheric asymmetry in the simulated dynamo results from the presence of an equator-symmetric part in the oscillating magnetic field. The sub-dominant quadrupolar oscillations are stochastically forced by dominant dipolar oscillations via the equator-symmetric part of the fluctuating α-effect. The amplitude and sense of the asymmetry of individual cycles varies on a timescale of the order of four dynamo-cycle periods. The variations are irregular and not periodic. The model suggests that asymmetry in the polar magnetic fields in the solar minima can be used as a precursor for asymmetry of sunspot activity in the following solar cycle.

scholarly journals Evolutionary aspects and north-south asymmetry of soft X-ray flare index during solar cycles 21, 22, and 23

2015 ◽  
Vol 582 ◽  
pp. A4 ◽  
Author(s):  
B. Joshi ◽  
R. Bhattacharyya ◽  
K. K. Pandey ◽  
U. Kushwaha ◽  
Yong-Jae Moon
Keyword(s):  
Solar Cycles ◽  
X Ray ◽  
Flare Index ◽  
Evolutionary Aspects ◽  
South Asymmetry

Periodic Variation of the North-South Asymmetry of Solar Activity Phenomena

2000 ◽  
Vol 179 ◽  
pp. 173-176
Author(s):  
V. K. Verma
Keyword(s):  
Solar Activity ◽  
Periodic Variation ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
Sunspot Data ◽  
Flare Index ◽  
North And South ◽  
South Asymmetry

AbstractWe report here a study of various solar activity phenomena occurring in both north and south hemispheres of the Sun during solar cycles 8–23. In the study we have used sunspot data for the period 1832–1976, flare index data for the period 1936–1993, Hα flare data 1993–1998 and solar active prominences data for the period 1957–1998. Earlier Verma reported long-term cyclic period in N-S asymmetry and also that the N-S asymmetry of solar activity phenomena during solar cycles 21, 22, 23 and 24 will be south dominated and the N-S asymmetry will shift to north hemisphere in solar cycle 25. The present study shows that the N-S asymmetry during solar cycles 22 and 23 are southern dominated as suggested by Verma.

The Long-term Behavior of the North – South Asymmetry of Sunspot Activity

Solar Physics ◽  
2008 ◽  
Vol 254 (1) ◽  
pp. 145-154 ◽  
Author(s):  
K. J. Li ◽  
P. X. Gao ◽  
L. S. Zhan
Keyword(s):  
Sunspot Activity ◽  
The North ◽  
Long Term Behavior ◽  
South Asymmetry
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