North-south distribution of solar flares during cycle 23

Abstract

In this paper, we investigate the spatial distribution of solar flares in the northern and southern hemisphere of the Sun that occurred during the period 1996 to 2003. This period of investigation includes the ascending phase, the maximum and part of descending phase of solar cycle 23. It is revealed that the flare activity during this cycle is low compared to previous solar cycle, indicating the violation of Gnevyshev-Ohl rule. The distribution of flares with respect to heliographic latitudes shows a significant asymmetry between northern and southern hemisphere which is maximum during the minimum phase of the solar cycle. The present study indicates that the activity dominates the northern hemisphere in general during the rising phase of the cycle (1997)(1998)(1999)(2000). The dominance of northern hemisphere is shifted towards the southern hemisphere after the solar maximum in 2000 and remained there in the successive years. Although the annual variations in the asymmetry time series during cycle 23 are quite different from cycle 22, they are comparable to cycle 21.

Study of Distribution and Asymmetry of Solar Active Prominences during Solar Cycle 23

“…The southern dominance of solar activity during SC 23 has been investigated by several authors by taking different solar activity features i.e. solar flares and CMEs (Joshi, Pant, and Manoharan, 2006;Gao, Li, and Zhong, 2007). Similar trend has been found in the present investigation with SAP data.…”

Seismic Transients from Flares in Solar Cycle 23

“…Interestingly, accordingly to Joshi et al (2006) solar activity dominated in the northern hemisphere during the rising phase of SC23 (1997)(1998)(1999)(2000). The dominance then moved to the southern hemisphere after the solar maximum in 2000.…”

The hemispheric variation of the flare index during solar cycles 20–23

“…The N-S asymmetries of different solar activities have been extensively studied by various authors (Maunder 1904;Newton & Milson 1955;Howard 1974;Knoska 1985;Vizoso & Ballester 1987;Oliver & Ballester 1994Atac & Ozguc 1996, 2001Verma 1987Verma , 1993Verma , 2000Joshi & Joshi 2004;Knaack et al 2004;Joshi et al 2006;Gao et al 2007Gao et al , 2009Yan et al 2008;Joshi et al 2009Joshi et al , 2010Bankoti et al 2010Bankoti et al , 2011Chang 2007, Corresponding author: bench@ynao.ac.cn 2009Cho & Chang 2011;Deng et al 2012a). Long-term observations of various solar activity phenomena indicate that their occurrence in the northern and southern hemispheres on the solar disk are not uniform, with more events occurring in one or the other hemisphere during certain periods of time.…”