摘要
通过对12-22周((1878-1995年)太阳大黑子群分布南北半球不对称的整体特征的研究,探讨了太阳活动周的长期演化趋势.约定N与S分别表示北南半球大黑子群数之和,BN与BS为北南半球大黑子群的纬度和.由这4个物理量定义了太阳活动周的3个参量:(1)太阳活动不对称指数AS=(N-S)/(N+S);(2)平均纬度BT=(BN+BS)/(N+S),BS取负值;(3)太阳活动带的宽度BW=BN/N-BS/S.对上述11个活动周,得到了有关80年周期的性质及奇偶数周大黑子群数变化的有意义的统计结果.
In this paper,the long term evolutionary trend of solar cycles is investigated on the basis of a statistical analysis of the north south asymmetry of the large sunspot groups in solar cycles Nos.12-22(1978-1995).The numbers of large spot groups in northern and southern hemispheres are denoted by N and S ,while the sums of spot groups' latitudes- B N and B S,respectively.Then three parameters are defined with the above four quantities, i.e. (1) the asymmetry index A S= (N-S)/(N+S); (2) the average latitude B T=( B N+ B S)/( N+S) ,where B S is negative;(3) the width of activity belt B W= B N/ N - B S/ S . The above mentioned 11 solar cycles yield the following statistical results.(1) The distributions of signs of A S and B T can be divided into three intervals:the 14th-20th cycles fall into positive intervals,while the other 4 cycles-negative ones.(2) When A S and B T are positive,the values of N-S for odd cycles are larger than those of the neighboring even cycles.When A S and B T are negative,the absolute values of N-S of even cycles are larger than those of odd ones.(3) When the absolute value of A S approaches 0.33 ( i.e.N/S or S/N is close to 2), A S changes sign.(4) B W exhibits a systematic evolution from its minimum,increasing at first and decreasing afterwards,in the time interval of 7 cycles. From the evolutionary trend of cycles Nos.12-22,it is speculated that the 23rd cycle would possess a southern hemisphere dominance in large sunspot activity.
出处
《天文学报》
CSCD
北大核心
1999年第2期142-148,共7页
Acta Astronomica Sinica
基金
国家基金委资助