ADVANCE Fellows Award: Investigating the Origins of Orbitally Forced Paleoclimates: The Interplay of Climate Response, Geodynamics, Astrodynamics and Earth Noise

这个ADVANCE研究员的职业发展计划的中心是研究轨道强迫古气候信号作为一阶地球动力学和天体动力学信息的载体。地球动力学理论预测，地球的潮汐耗散和动力椭圆性会扰乱地球的轴向进动率和倾斜。在古气候记录的轨道模式中，扰动应表现为相位不规则。对这些不规则现象的观测取决于赋予古气候记录的时间尺度的准确性。这通常涉及根据假设的气候对轨道强迫的响应，将记录中解释的轨道信号调整为“目标”曲线。然而，如果目标是错误的，时序误差将破坏记录的轨道模式的真实相位。在这个误差源得到有效控制之前，我们不应该从古气候记录中得出关于地球物理行为的确切结论。天体动力学理论表明，地球轨道模式的长周期振幅和频率调制跟踪行星轨道运动；这些应该可以在很长的古气候信号中检测到。有些行星的轨道会产生共振，例如地球和火星；在遥远的过去，火星和地球的轨道可能在两种共振状态之间混乱地移动。因此，利用古气候记录验证这种行为是天体动力学的首要任务。然而，使这些信息的提取变得复杂的是低频的“地球噪声”，它会干扰长时间的古气候信号。为了解决这些问题，将开发一个多任务计算机模型，计算任何地理位置在任何时间尺度上的日晒，并与可调节的旋转轨道参数相关联，这些参数包括地球潮汐耗散和动力椭圆性的影响。该模型将在一系列敏感性实验中进行探索，然后使用先进的时间序列分析对古气候记录进行评估。

Hinnov0137799This ADVANCE Fellows career-development plan centers on an investigation of orbitally forced paleoclimate signals as carriers of first order geodynamical and astrodynamical information. Geodynamical theory predicts that the Earth's tidal dissipation and dynamical ellipticity will perturb the Earth's axial precession rate and tilt. The perturbations should appear in paleoclimatically recorded orbital modes as phasing irregularities. Observation of these irregularities depends upon the accuracy of the timescale assigned to the paleoclimate record. This typically involves adjusting an interpreted orbital signal in the record to a "target" curve based upon an assumed climate response to orbital forcing. If the target is wrong, however, timing errors will corrupt the true phasing of the recorded orbital modes. Until this source of error can be effectively managed, no firm conclusions about the Earth's physical behavior should be drawn from the paleoclimate record. Astrodynamical theory indicates that long-period amplitude and frequency modulations in the Earth's orbital modes track planetary orbital motions; these should be detectable in very long paleoclimate signals. Some planetary orbits resonate, e.g., Earth and Mars; in the remote past, the orbits of Mars and Earth may have moved chaotically between two resonance states. Verification of this behavior using the paleoclimate record is therefore a top priority in astrodynamics. Complicating the extraction of this information, however, is low frequency "Earth noise" that can interfere with long paleoclimate signals. To unravel these problems, a multi-task computer model will be developed that calculates insolation at any geographical location over any timescale, and is linked to adjustable rotational-orbital parameters that include effects from the Earth's tidal dissipation and dynamical ellipticity. The model will be explored in a series of sensitivity experiments, then evaluated against paleoclimate records using advanced time series analysis.