12000年以来天文季节长度变化序列的重建及其特征分析

Reconstruction and analysis of the variation of astronomical seasonal length since 12000 years BP

已有研究发现季节长度变化与气候冷暖变化密切相关,但是到目前为止还没有一个长度超过1万年的准确度很高的季节长度变化序列.该文利用星历数据DE441重建了12000年以来季节长度的时间变化序列,并利用ICEEMDAN与连续小波变换两种方法提取了夏季与冬季长度不同尺度的周期性信号,揭示了它们在过去12000年以来不同时间段内的变化特征.研究发现:北半球夏季时长变化存在2.5年、4年、5.5年、11.8年、15.8年、29年、84年、101年、223年、约500年和约850年的周期,北半球冬季时长变化具有2.5年、4年、5.5年、11.8年、15.8年、29年、74年、167年、约500年和约1000年的周期.其中11.8年的短尺度周期变化贯穿于整个过去12000年;2.5年、4年、5.5年与15.8年左右的周期则是在全新世某个时间段内变化较为显著.该研究结果为进一步深入理解和探讨气候变化的原因和机制提供了新的数据和依据.

Previous studies have found that seasonal length changes are closely related to climate changes,but so far there is no highly accurate seasonal length change sequence with a length exceeding 10000 years.This article uses ephemeris data DE441 to reconstruct the time series of seasonal length changes since 12000 years,and uses two methods,ICEEMDAN and continuous wavelet transform,to extract periodic signals of different scales of summer and winter length,revealing their changing characteristics in different time periods over the past 12000 years.Research has found that there are cycles of 2.5 years,4 years,5.5 years,11.8 years,15.8 years,29 years,84 years,101 years,223 years,approximately 500 years,and approximately 850 years in the summer duration of the Northern Hemisphere,while there are cycles of 2.5 years,4 years,5.5 years,11.8 years,15.8 years,29 years,74 years,167 years,approximately 500 years,and approximately 1000 years in the winter duration of the Northern Hemisphere.The short scale periodic variation of 11.8 years runs through the entire past 12000 years;The cycles of 2.5 years,4 years,5.5 years and 15.8 years are relatively significant in a certain period of Holocene.The research results provide new data and basis for further understanding and exploring the causes and mechanisms of climate change.