A STUDY OF VARIATION OF THE 11-YR SOLAR CYCLE BEFORE THE ONSET OF THE SPOERER MINIMUM BASED ON ANNUALLY MEASURED 14C CONTENT IN TREE RINGS
A STUDY OF VARIATION OF THE 11-YR SOLAR CYCLE BEFORE THE ONSET OF THE SPOERER MINIMUM BASED ON ANNUALLY MEASURED 14C CONTENT IN TREE RINGS
复制标题
DOI：
10.1017/rdc.2019.123
复制
发表时间：
2019-12-01
期刊：
影响因子：
8.3
通讯作者：
Tokanai, Fuyuki
中科院分区：
文献类型：
--
作者：
Moriya, Toru;Miyahara, Hiroko;Tokanai, Fuyuki
过去基于代用资料对太阳活动的观测揭示了长期变化，比如格莱斯堡周期（约88年）、德弗里斯周期（约200年）以及哈尔施塔特周期（约2000年）。太阳活动的这种长期变化有时会导致太阳黑子消失数十年。目前，太阳活动正在变弱，有可能会出现另一个长期的太阳黑子极小期。然而，太阳活动减弱的详细机制尚不清楚，对太阳活动的预测也不明确。在这项研究中，我们调查了斯波勒极小期（过去2000年中最长的大极小期）开始之前太阳活动周期长度的转变。我们使用山形大学的紧凑型加速器质谱仪系统测量了从公元1368年到1420年在下北半岛挖掘出的罗汉柏（Thujopsis dolabrata）中的碳 - 14含量。研究发现，从斯波勒极小期开始前的2个周期起，太阳活动周期延长至14 - 16年。
Proxy-based observations of solar activity in the past have revealed long-term variations, such as the Gleissberg cycle (similar to 88 yr), de Vries cycle (similar to 200 yr), and the Hallstatt cycle (similar to 2000 yr). Such long-term variations of solar activity sometimes cause the disappearance of sunspots for several decades. Currently, solar activity is becoming weaker, and there is a possibility that another long-term sunspot minimum could occur. However, the detailed mechanism of the weakening in solar activity is unknown, and the prediction of solar activity is ambiguous. In this study, we investigate the transitions of solar cycle length before the onset of the Spoerer Minimum, the longest grand minimum in the past 2000 yr. We measured the C-14 content in an asunaro tree (Thujopsis dolabrata) excavated at Shimokita Peninsula from 1368-1420 CE using the compact AMS system at Yamagata University. It is found that the solar cycle lengthened to be 14-16 yr from 2 cycles before the onset of the Spoerer Minimum.