Links between eccentricity forcing and the 100,000-year glacial cycle
Links between eccentricity forcing and the 100,000-year glacial cycle
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DOI：
10.1038/ngeo828
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发表时间：
2010-05-01
影响因子：
18.3
通讯作者：
Lisiecki, Lorraine E.
中科院分区：
文献类型：
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作者：
Lisiecki, Lorraine E.
地球轨道的偏心率（100，000年）、旋度（41，000年）和岁差（23，000年）的变化与冰川-间冰期气候周期有关。一般认为，过去80万年的10万年冰期循环是轨道偏心率的结果（1-4）。然而，偏心周期产生的季节或平均年日照可忽略不计的100 kyr功率，虽然它调制的岁差周期的振幅。另一种观点认为，最近的冰期旋回完全是由冰期旋回驱动的（5-7）。在这里，我使用统计分析的日照和气候的过去五百万年来的特点偏心率和10万年的冰川周期之间的联系。使用交叉小波相位分析，我表明偏心率和冰川周期的相对相位自120万年前以来一直稳定，支持10万年冰川周期由偏心率（4，11）定步调（8-10）的假设。然而，我发现，随时间变化的100，000年的功率偏心率已与气候的500万年前以来，与较弱的功率在100，000年的冰川周期与强大的偏心率强迫相关。我建议，这种关系产生于与强离心力相关的强岁差强迫，这破坏了驱动10万年冰川周期的内部气候反馈。这支持了内部驱动的气候反馈是10万年气候变化的来源的假设（12）。
Variations in the eccentricity (100,000 yr), obliquity (41,000 yr) and precession (23,000 yr) of Earth's orbit have been linked to glacial-interglacial climate cycles. It is generally thought that the 100,000-yr glacial cycles of the past 800,000 yr are a result of orbital eccentricity(1-4). However, the eccentricity cycle produces negligible 100-kyr power in seasonal or mean annual insolation, although it does modulate the amplitude of the precession cycle. Alternatively, it has been suggested that the recent glacial cycles are driven purely by the obliquity cycle(5-7). Here I use statistical analyses of insolation and the climate of the past five million years to characterize the link between eccentricity and the 100,000-yr glacial cycles. Using cross-wavelet phase analysis, I show that the relative phase of eccentricity and glacial cycles has been stable since 1.2 Myr ago, supporting the hypothesis that 100,000-yr glacial cycles are paced(8-10) by eccentricity(4,11). However, I find that the time-dependent 100,000-yr power of eccentricity has been anticorrelated with that of climate since 5 Myr ago, with strong eccentricity forcing associated with weaker power in the 100,000-yr glacial cycle. I propose that the anticorrelation arises from the strong precession forcing associated with strong eccentricity forcing, which disrupts the internal climate feedbacks that drive the 100,000-yr glacial cycle. This supports the hypothesis that internally driven climate feedbacks are the source of the 100,000-yr climate variations(12).