太阳活动周的半球耦合模式及驱动机制的探索研究

Solar activity cycle and dynamo theories, which explain the temporal evolution and the physical origin of solar magnetic structures, are the fundamental and essential questions in the fields of solar physics. With the help of the historical data of hand-drawing sunspots and vector magnetic fields in China and the revisited sunspot data sets complied by various observatories all over the world, it is the best time to investigate the hemispheric coupling and the physical mechanism of solar magnetic acitivity on both hemispheres. This project is intended to carry out the investigation in the following contents: 1) to search the systematic regularities of the amplitude asymmetry and the phase asynchronism of hemispheric magnetic activities in different solar cycles; 2) to establish the statistical intercorrelation between the quasi-biennial oscillation (QBO) and Rieger-type periodicity (RTP) and the instabilities of magnetic Rossby wave in the solar tachocline; 3) to find the causal relationship among the coupling degree of hemispheric sunspot data, the speed of the meridional circulation, the asymmetric polar field reversals, and the secular trend of magnetic fields; 4) to inspect whether the increased level of hemispheric difference of solar activity is the forewarning indication of the grand minima, and to evaluate the reproducing probability of the grand minima similar to the Maunder minimum. From the statistical and theoretical studies, we expect that the analysis results could provide some valuable information for the potential coupling mechanism of hemispheric magnetic activities, and could promote and constraint the global dynamo theories.

太阳活动周和发电机理论是太阳物理最基本和最核心的前沿科学问题。我国太阳界陆续发布最新整编的手绘黑子和矢量磁场数据，国外多个观测台站近期也重新校准了历史时序数据，这为探究太阳活动在南北半球上的耦合模式和物理成因提供了一个绝佳的研究时机。本项目拟从发电机模型和数据统计的角度开展以下四个方面的工作:(1)寻找太阳半球活动在不同活动周的幅度不对称性和相位不同时性的系统性演化特征;(2)建立准双年振荡和类丽格尔周期的半球差异与强剪切层里的罗斯贝波不稳定性的统计相关性;(3)太阳半球活动的耦合程度增强或减弱与子午环流速度、极性反转时间和磁场变化趋势的因果关系;(4)考察持续增强的半球差异程度是否是孕育超级极小期的征兆指标，并对再现类似于蒙德极小期的可能性进行定量评估。通过统计和模拟研究，期望为探究太阳半球活动的潜在耦合机制提供有价值的观测证据，并对建立和检验更合理的发电机模型提供必要的约束条件。