摘要
为研究地球自转速率变化的非线性特性,结合自适应噪声完备经验模态分解、定量递归分析和Grassberger-Procaccia算法,从周期、混沌和分形多角度对1962年1月1日至2023年12月31日反映地球自转速率变化的日长变化(length of day,ΔLOD)观测序列的非线性特性进行全面分析,并着重对比分析扣除周期成分或混沌成分前后ΔLOD特性是否存在明显区别.主要结论如下:1)ΔLOD时间序列由趋势成分、周期成分和混沌成分构成,具有明显的多时间尺度、混沌动力学特性和分形结构;2)扣除混沌成分后的时间序列周期与原始ΔLOD时间序列的周期完全相同;3)原始ΔLOD时间序列和其扣除趋势成分和周期成分后的时间序列的混沌特性无显著性差异,但前者分形结构的复杂性相对更强.
Abstract
To study the nonlinear characteristics of changes in the Earth's rotation rate,a comprehensive analysis of the nonlinear characteristics of the length of day(ΔLOD)observations reflecting changes in the Earth's rotation rate is conducted from multiple perspectives,including periodicity,chaos,and fractal,by using the complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN),recursive quantitative analysis(RAQ),and Grassberger-Procaccia(GP)algorithms.The long-term high-accuracy ΔLOD observations from January 1,1962 to December 31,2023,were comprehensively and reliably analyzed and then used as dataset published by the International Earth Rotation and Reference Systems Service,IERS)14C04 series.The present workfocuses on comparing and analyzing whether there are any significant differences in the ΔLOD characteristics before and after deducting the periodic or chaotic components of ΔLOD time series.The main conclusions obtained are as follows.1)The ΔLOD time series consists of the well-known trend components,many periodic components,and chaotic components,and therefore can be characterized by obvious multi timescales,chaotic dynamics,and fractal structure.The characteristics were not considered in previous research.2)The period of the ΔLOD time series after deducting the chaotic components is exactly the same as the period of the original ΔLOD time series,implying that the chaotic components have no effects on reconstruction nor analysis of the periodic components.3)There is no significant difference in chaotic characteristics between the original ΔLOD time series and its time series after deducting trend and periodic components,but the complexity of the fractal structure of the former is relatively stronger.Not only can this work provide a valuable reference for studying the mechanism of changes in the Earth's rotation rate,but also model such rotation changes and then predict the chances on different timescales.
基金项目
陕西省自然科学基础研究计划(2023-JC-YB-057)
中国科学院青年创新促进会资助()
国家科技期刊平台
NSTL
万方数据