Lourens L J, Wehausen R, Brumsack H J
Faculty of Earth Sciences, Utrecht University, The Netherlands.
Nature. 2001 Feb 22;409(6823):1029-33. doi: 10.1038/35059062.
The evolution of the Solar System has been shown to be chaotic, which limits our ability to retrace the orbital and precessional motion of the Earth over more than 35-50 Myr (ref. 2). Moreover, the precession, obliquity and insolation parameters can also be influenced by secular variations in the tidal dissipation and dynamical ellipticity of the Earth induced by glacial cyclicity and mantle convection. Here we determine the average values of these dissipative effects over the past three million years. We have computed the optimal fit between an exceptional palaeoclimate record from the eastern Mediterranean Sea and a model of the astronomical and insolation history by testing a number of values for the tidal dissipation and dynamical ellipticity parameters. We find that the combined effects of dynamical ellipticity and tidal dissipation were, on average, significantly lower over the past three million years, compared to their present-day values (determined from artificial satellite data and lunar ranging). This secular variation associated with the Plio-Pleistocene ice load history has caused an average acceleration in the Earth's rotation over the past 3 Myr, which needs to be considered in the construction of astronomical timescales and in research into the stationarity of phase relations in the ocean-climate system through time.
太阳系的演化已被证明是混沌的，这限制了我们追溯超过3500万至5000万年期间地球轨道和岁差运动的能力（参考文献2）。此外，岁差、倾角和日照参数还会受到冰川旋回和地幔对流引起的地球潮汐耗散和动力扁率长期变化的影响。在此，我们确定了过去300万年中这些耗散效应的平均值。通过测试潮汐耗散和动力扁率参数的多个值，我们计算出了东地中海一份特殊古气候记录与天文和日照历史模型之间的最佳拟合。我们发现，与现今值（由人造卫星数据和月球测距确定）相比，过去300万年中动力扁率和潮汐耗散的综合效应平均显著降低。这种与上新世 - 更新世冰负载历史相关的长期变化在过去300万年中导致了地球自转的平均加速，这在构建天文时间尺度以及研究海洋 - 气候系统相位关系随时间的平稳性时需要加以考虑。
