Milankovitch band forcing of sub‐Milankovitch climate variability during the Pleistocene
Milankovitch band forcing of sub‐Milankovitch climate variability during the Pleistocene
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DOI：
10.1029/94pa00443
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发表时间：
1994-08
期刊：
影响因子：
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通讯作者：
T. Hagelberg;G. Bond;P. deMenocal
中科院分区：
文献类型：
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作者：
T. Hagelberg;G. Bond;P. deMenocal
在晚更新世的三个地点(东赤道太平洋钻探计划站点846、赤道东部大西洋ODP站663和东北大西洋深海钻探项目站点609)量化了源于米兰科维奇波段强迫的10KYR到12KYR周期的气候变异性。主要的米兰科维奇强迫中不存在这些周期的变率，因此不可能与米兰科维奇波段变化有线性联系。然而，这些周期等于进动带振荡的谐波。在不同时间尺度上发生的过程之间的相互作用的大小只能通过应用高阶统计量在时间序列数据中得到解决。通过这样的应用，我们证明了沉积物记录中10-12 KYR波段的方差中有75%是由进动波段(19-23KYR)的变化非线性转换而来的。在千禧年到亚米兰科维奇频段内，定义为从∼15到∼2 Kyr的变化频带，所研究记录中大约三分之一的变异性与低频率的米兰科维奇频带来源一致。这种变化可能源于热带地区对夏季两半球的日照相对冬季日照的高度敏感。一种起源于赤道并与低纬进动变化有关的机制似乎与观测一致。由于10到12 KYR振荡和进动之间的位相耦合得到了解决，这一结果对于寻求解释该时间尺度上全球气候变化的模型的发展具有重要意义。
Climate variability at periods from 10 kyr to 12 kyr that originates from Milankovitch band forcing is quantified at three locations for the late Pleistocene (eastern equatorial Pacific Ocean Drilling Program site 846, eastern equatorial Atlantic ODP site 663, and northeastern Atlantic Deep Sea Drilling Project site 609). Variability at these periods is not present in the primary Milankovitch forcing, so no linear linkage to Milankovitch band variations is possible. However, these periods are equal to harmonics of precession band oscillations. The magnitude of interactions between processes that occur at different timescales can only be resolved in time series data through application of higher-order statistics. Through such an application, we demonstrate that up to 75% of the variance in the 10- to 12-kyr band in the sediment records is nonlinearly transferred from precession band (19–23 kyr) variations. Within the millennial to sub-Milankovitch band, defined as the band of variance ranging from ∼15 to ∼2 kyr, approximately 1/3 of the variability in the records studied is consistent with a low-frequency, Milankovitch band origin. This variability may derive from high sensitivity of the tropics to summertime insolation in both hemispheres relative to wintertime insolation. A mechanism having equatorial origin and related to low-latitude precession variations appears consistent with the observations. Because the phase coupling between 10- to 12-kyr oscillations and precession is resolved, this result has implications for development of models which seek to explain global climate variations on this timescale.