摘要
太阳内部和表面大气存在不同尺度的准周期变化,特别是准双年振荡(quasi-biennial oscillations,QBOs)在日地空间物理领域中受到了广泛关注.本文以1963—2018年期间的太阳风速度的日变化作为研究对象,研究QBOs对太阳风速度的影响,并揭示其非线性演化特征.基于动力系统中的不规则性指数来度量太阳风速度随时间变化的复杂性和不规则性,并揭示太阳活动中潜在的非线性变化信息,从而进一步研究QBOs的时间分布.结果发现:(1)太阳风速度的不规则性指数在一个太阳活动周内经历了两次振荡,即存在准5.5年的周期变化;(2)太阳风速度的不规则程度在1996年附近发生了明显增强,即太阳活动较弱的第23和第24活动周的复杂性比之前高;(3)通过一阶自回归模型,发现周期尺度为1.3年和1.7年的QBOs在1996年之后对太阳风速度的影响更为明显,即第23活动周之后太阳磁场的变化与QBOs紧密相关.研究结果表明:QBOs不仅对推进太阳发电机的动力学演化有科学价值,而且对日地空间环境的耦合过程有重要意义.
Quasi-biennial oscillations(QBOs)are common periodic scales in the solar activity indices and are currently receiving much attention in Sun-Earth space physics field.Here,we study the long-term evolutions of their nonlinear characteristics based on the daily solar wind velocity from 1963 to 2018,and discuss the effect of the QBOs on the nonlinear variations of the solar wind.We use the irregularity index in the dynamical system to measure the complexity and irregularity of solar wind activities varying with the time.This method reveals the latent nonlinear variation information in solar activity,which is helpful to further study the time distribution of mid-term periodicities such as QBOs.The results show:(1)The irregularity index shows a quasi-5.5-year variations,which means the irregularity nearly oscillates twice in a Schwabe cycle.(2)The irregularity of solar activity has increased significantly since 1996,which means the weak cycles 23 and 24 show more complexity than before.(3)Combined with the fitting results of the model,we find that the quasi-biennial oscillation of 1.3-year and 1.7-year experienced an evident augment after this period.This may suggest that the changes of the internal activity within the sun after the cycle 23 are closely linked to the intensification of the QBOs.The results show that QBOs not only has scientific values in promoting the dynamic evolution of solar dynamo,but also has important significance in the coupling process of solar-terrestrial space environment.
作者
费宇
陈卓
邓林华
李春
梁家卷
FEI Yu;CHEN Zhuo;DENG LinHua;LI Chun;LIANG JiaJuan(School of Statistics and Mathematics,Yunnan University of Finance and Economics,Kunming 650221,China;School of Mathematics and Computer Science,Yunnan Minzu University,Kunming 650504,China;BNU-HKBU United International College,Zhuhai Guangdong 519087,China)
出处
《地球物理学报》
北大核心
2025年第9期3291-3302,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金(11971421)
云南省“兴滇英才支持计划”云岭学者专项(YNWR-YLXZ-2018-020)
云南财经大学校级项目(2024H59)
云南省“兴滇英才支持计划”创新团队专项(202405AS350012)
北师香港浸会大学广东省重点实验室项目(UICR0400026-21,2022B1212010006)联合资助.
关键词
太阳风
准双年振荡
非线性动力学
自回归模型
Solar wind
Quasi-biennial oscillations(QBOs)
Nonlinear dynamics
Autoregressive model
