Regularity of the north-south asymmetry of solar activity

Li, K. J.; Wang, J. X.; Xiong, S. Y.; Liang, Hong; Yun, Hong Sik; Gu, Xiaoxia

doi:10.1051/0004-6361:20011799

Cited by 114 publications

(68 citation statements)

References 30 publications

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“…In the same figure it can also be seen that there is a strong suggestion of the existence of the ≈44-year periodicity in both δA(T * m ) and δA(T * M ). A 33 -44 year periodicity is also found in the power spectrum analysis of the data on north-south asymmetries in sunspot activity (Javaraiah and Gokhale, 1997;Li et al, 2002;Ballester, Oliver, and Carbonell, 2005) and long-lived solar filaments (Duchlev and Dermendjiev, 1996). This periodicity is dominant in the north-south asymmetries of the solar equatorial and the differential rotation rates determined from sunspot group data (Javaraiah and Gokhale, 1997), and it seems to be present prominently in the climatically related phenomena and in the Earth rotation rate, which may be related to the 44-year cycle (double Hale cycle) of solar magnetic activity (Fairbridge and Hillaire-Marcel, 1977;Georgieva, 2002).…”

Section: Datamentioning

confidence: 65%

Predicting the Amplitude of a Solar Cycle Using the North – South Asymmetry in the Previous Cycle: II. An Improved Prediction for Solar Cycle 24

Javaraiah

2008

Sol Phys

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Recently, using Greenwich and Solar Optical Observing Network sunspot group data during the period 1874 -2006, Javaraiah (Mon. Not. Roy. Astron. Soc. 377, L34, 2007: Paper I), has found that: (1) the sum of the areas of the sunspot groups in 0• -10• latitude interval of the Sun's northern hemisphere and in the time-interval of −1.35 year to +2.15 year from the time of the preceding minimum of a solar cycle n correlates well (corr. coeff. r = 0.947) with the amplitude (maximum of the smoothed monthly sunspot number) of the next cycle n+1. (2) The sum of the areas of the spot groups in 0• -10 • latitude interval of the southern hemisphere and in the time-interval of 1.0 year to 1.75 year just after the time of the maximum of the cycle n correlates very well (r = 0.966) with the amplitude of cycle n + 1. Using these relations, (1) and (2), the values 112 ± 13 and 74 ± 10, respectively, were predicted in Paper I for the amplitude of the upcoming cycle 24. Here we found that the north-south asymmetries in the aforementioned area sums have a strong ≈ 44-year periodicity and from this we can infer that the upcoming cycle 24 will be weaker than cycle 23. In case of (1), the north-south asymmetry in the area sum of a cycle n also has a relationship, say (3), with the amplitude of cycle n + 1, which is similar to (1) but more statistically significant (r = 0.968) like (2). By using (3) it is possible to predict the amplitude of a cycle with a better accuracy by about 13 years in advance, and we get 103 ± 10 for the amplitude of the upcoming cycle 24. However, we found a similar but a more statistically significant (r = 0.983) relationship, say (4), by using the sum of the area sum used in (2) and the north-south difference used in (3). By using (4) it is possible to predict the amplitude of a cycle by about 9 years in advance with a high accuracy and we get 87 ± 7 for the amplitude of cycle 24, which is about 28% less than the amplitude of cycle 23. Our results also indicate that cycle 25 will be stronger than cycle 24. The variations in the mean meridional motions of the spot groups during odd and even numbered cycles suggest that the solar meridional flows may transport magnetic flux across the solar equator and potentially responsible for all the above relationships.

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Section: Datamentioning

confidence: 65%

Predicting the Amplitude of a Solar Cycle Using the North – South Asymmetry in the Previous Cycle: II. An Improved Prediction for Solar Cycle 24

Javaraiah

2008

Sol Phys

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“…With the butterfly diagram, we can study the detailed evolution of the latitude distribution of sunspots and, thus, the dynamo wave propagation (e.g., Newton & Milsom 1955;Carbonell et al 1993;Pulkkinen et al 1999;Li et al 2002;Ballester et al 2005;Berdyugina et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Wings of the butterfly: Sunspot groups for 1826–2015

Leussu

Usoskin

Pavai

et al. 2017

A&A

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The spatio-temporal evolution of sunspot activity, the so-called Maunder butterfly diagram, has been continously available since 1874 using data from the Royal Greenwich Observatory, extended by SOON network data after 1976. Here we present a new extended butterfly diagram of sunspot group occurrence since 1826, using the recently digitized data from Schwabe (1826Schwabe ( -1867 and Spörer (1866Spörer ( -1880. The wings of the diagram are separated using a recently developed method based on an analysis of long gaps in sunspot group occurrence in different latitude bands. We define characteristic latitudes, corresponding to the start, end, and the largest extent of the wings (the F, L, and H latitudes). The H latitudes (30 • -45 • ) are highly significantly correlated with the strength of the wings (quantified by the total sum of the monthly numbers of sunspot groups). The F latitudes (20 • -30 • ) depict a weak tendency, especially in the southern hemisphere, to follow the wing strength. The L latitudes (2 • -10 • ) show no clear relation to the wing strength. Overall, stronger cycle wings tend to start at higher latitudes and have a greater wing extent. A strong (5-6)-cycle periodic oscillation is found in the start and end times of the wings and in the overlap and gaps between successive wings of one hemisphere. While the average wing overlap is zero in the southern hemisphere, it is two to three months in the north. A marginally significant oscillation of about ten solar cycles is found in the asymmetry of the L latitudes. The new long database of butterfly wings provides new observational constraints to solar dynamo models that discuss the spatio-temporal distribution of sunspot occurrence over the solar cycle and longer.

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“…We also study the hemispheric asymmetry of wings, which is often known to be significant and to produce fairly systematic phenomena (see e.g. Newton & Milsom 1955;Carbonell et al 1993;Verma 1993;Pulkkinen et al 1999;Li et al 2002;Mursula & Hiltula 2003;Ballester et al 2005;Virtanen & Mursula 2010, 2014. This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

Properties of sunspot cycles and hemispheric wings since the 19th century

Leussu

Usoskin

Arlt

et al. 2016

A&A

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Aims. The latitudinal evolution of sunspot emergence over the course of the solar cycle, the so-called butterfly diagram, is a fundamental property of the solar dynamo. Here we present a study of the butterfly diagram of sunspot group occurrence for cycles 7-10 and 11-23 using data from a recently digitized sunspot drawings by Samuel Heinrich Schwabe in 1825-1867, and from RGO/USAF/NOAA(SOON) compilation of sunspot groups in 1874-2015. Methods. We developed a new, robust method of hemispheric wing separation based on an analysis of long gaps in sunspot group occurrence in different latitude bands. The method makes it possible to ascribe each sunspot group to a certain wing (solar cycle and hemisphere), and separate the old and new cycle during their overlap. This allows for an improved study of solar cycles compared to the common way of separating the cycles. Results. We separated each hemispheric wing of the butterfly diagram and analysed them with respect to the number of groups appearing in each wing, their lengths, hemispheric differences, and overlaps. Conclusions. The overlaps of successive wings were found to be systematically longer in the northern hemisphere for cycles 7-10, but in the southern hemisphere for cycles 16-22. The occurrence of sunspot groups depicts a systematic long-term variation between the two hemispheres. During Schwabe time, the hemispheric asymmetry was north-dominated during cycle 9 and south-dominated during cycle 10.

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Regularity of the north-south asymmetry of solar activity

Cited by 114 publications

References 30 publications

Predicting the Amplitude of a Solar Cycle Using the North – South Asymmetry in the Previous Cycle: II. An Improved Prediction for Solar Cycle 24

Predicting the Amplitude of a Solar Cycle Using the North – South Asymmetry in the Previous Cycle: II. An Improved Prediction for Solar Cycle 24

Wings of the butterfly: Sunspot groups for 1826–2015

Properties of sunspot cycles and hemispheric wings since the 19th century

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