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南北半球太阳表面(较差)自转长期演化研究
Alternative TitleLong-term Variation of the Northern and Southern Hemispheric Solar Surface (Differential) Rotation
谢婧岚
Subtype硕士
Thesis Advisor李可军
2012-05-28
Degree Grantor中国科学院研究生院(云南天文台)
Place of Conferral北京
Degree Discipline天体物理
Keyword太阳活动 太阳自转 太阳黑子
Abstract较差自转是实现极向磁场向环向磁场转换的一个重要机制,是解释太阳活动起源的太阳发电机理论的基础。但是,关于较差自转是如何影响太阳磁活动周变化的,目前尚不清楚。因此,研究较差自转随太阳周的变化以及较差自转的南北不对称性,不仅对于理解太阳内部动力学过程、太阳活动周机制和太阳磁活动变化至关重要,而且能推动关于较差自转产生和维持的理论模型的研究向前发展。 本文分为三个部分, 第一章,太阳表面较差自转的概述,先简单地介绍了较差自转研究的历史、太阳表面较差自转的两种观测方法(示踪法和光谱法)和主要的一些观测结果,接着分四个方面介绍了太阳自转速度随时间变化的一些研究结果,包括太阳自转的长期变化趋势、太阳自转随太阳周相位的变化、太阳自转随时间变化的周期性和太阳自转的南北不对称性,最后简单地介绍了产生和维持较差自转的可能机制。 第二章,我们对1945年1月1日到2010年12月31日的每日半球黑子数进行了小波功率谱分析,得到全日面、北半球和南半球的太阳自转周期长度数据,研究了全日面和南北半球的太阳自转周期长度随时间的变化,得到的主要结果如下: 1.自相关分析的结果表明,在我们所研究的时间内,南半球比北半球整体转得更快。 2.对小波功率谱分析得到的自转周期长度随时间变化进行研究的结果表明,自转周期的长期变化趋势和太阳活动的长期变化趋势没有直接关系。 3.南北半球的自转周期变化都没有11年的变化周期,但都存在7.6年左右的变化周期。 4.对太阳自转周期长度随太阳周相位的变化的研究表明,在太阳活动极小前的一段时间,自转较快。 5.南北半球的自转周期长度变化存在相位差。自转周期长度和太阳活动之间存在相位差。 6.自转周期的南北不对称值存在7.7年和17.5年的变化周期,且其与每日太阳黑子数的南北不对称值之间具有较好的相关性,从而可以预测在太阳活动24周开始的一段时间内,北半球转得比南半球更快。 第三章,结束语,指出了太阳自转速度研究方面还有很多相关的疑问没有得到较好的解释, 并对我们未来工作可以从哪些方面深入做了展望。
Other AbstractDifferential rotation plays a key role in providing toroidal magnetic field from the poloidal one for solar activity. It is generally agreed that the Sun's differential rotation drives the solar dynamo for generating all solar activity. However, the role of the differential rotation as a participant in the cycle of magnetic activity variation is not yet clear. Hence, study of the variations of differential rotation during the solar cycle and its north-south asymmetry is essential for understanding the mechanism of the solar cycle, the Sun's internal dynamics and the variations in the solar magnetic activity, as well as for finding the cause of the variations in the differential rotation. In chapter one, on the base of surveying a number of references, we summarized the basic knowledge of solar surface differential rotation. The history of the study of solar rotation, the two basic methods used in investigating the solar rotation rate and some important research results of the solar rotation are introduced first. Then some main results of temporal variation of solar rotation are reviewed including the long-term variation, the solar-cycle dependent, the periodicity and the north-south asymmetry. Finally, some theories study for what cause the differential rotation and what maintains it are summarized simply. In chapter two, the daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from 1945 January 1 to 2010 December 31 are used to investigate the temporal variation of rotational cycle length through the continuous wavelet transformation analysis method. The main results are listed as follows: 1. Auto-correlation function analysis of daily hemispheric sunspot numbers shows that the southern hemisphere rotates faster than the northern hemisphere. 2. The results obtained from the wavelet transformation analysis are that no direct relationship exists between the variation trend of the rotational cycle length and the solar activity in the two hemispheres. 3.The rotational cycle length of both hemispheres has no significant period appearing at 11 yr, but has a significant period of about 7.6 yr. 4.Analysis concerning the solar cycle dependence of the rotational cycle length shows that acceleration seems to appear before the minimum time of solar activity in the whole disk and the northern hemisphere, respectively. 5.Furthermore, the cross-correlation study indicates that the rotational cycle length of the two hemispheres has different phases, and that the rotational cycle length of the whole disk as well as the northern and southern hemispheres, also has phase shifts with corresponding solar activity. 6. the temporal variation of the north-south (N-S) asymmetry of the rotational cycle length is also studied. This displays the same variation trend as the N-S asymmetry of solar activity in a solar cycle, as well as in the considered time interval, and has two significant periods of 7.7 and 17.5 yr. Moreover, the rotational cycle length and the N-S asymmetry of solar activity are highly correlated. It is inferred that the northern hemisphere should rotate faster at the beginning of solar cycle 24. In the last chapter, some unsolved questions about the solar differential rotation are given and what I can do to further my study in the next stage are presented.
Subject Area天文学
Language中文
Document Type学位论文
Identifierhttp://ir.ynao.ac.cn/handle/114a53/6617
Collection太阳物理研究组
Recommended Citation
GB/T 7714
谢婧岚. 南北半球太阳表面(较差)自转长期演化研究[D]. 北京. 中国科学院研究生院(云南天文台),2012.
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