Coupling the Dynamics of Earth's Core and Mantle / Core-Mantle-Coup

自从Glatzmaier等人1999年的开创性工作以来，人们已经认识到地幔对液态铁核中的发电机作用施加了关键控制。通过核幔边界（CMB）的核热损失的量和模式影响磁场强度，几何形状和动力学，包括其反转率。在这里，我们建议利用最近取得的巨大进展，地幔对流和发电机模拟能力，调查这一一阶过程的核心和地幔耦合超过1亿年的时间跨度，从神秘的白垩纪正常超时（CNS）到今天。逆转率从CNS期间的极少数逆转增加到约每百万年4次。为发电机和地幔动力学提供了重要的约束。我们的地幔对流模拟将通过高分辨率模型中的伴随方法利用最先进的地球动力学数据同化技术，应用超过6.7亿个网格点来离散地球地幔，以及时追溯全球地幔流，并跟踪整个CMB的核心热损失的幅度和模式。地质约束过去的动态地形将有助于通知选择最佳的地球动力学模拟参数用于地幔流轨迹。在地幔岩成分的等化学动力学地球模型旁边，我们将带来新的热化学伴随技术来承担，以追溯地幔流动的假设下，大的动态孤立的地幔域，特别是LLSVP。不同参数组合下的最新发电机模拟将探索不同CMB热通量模式对地球发电机的影响。无论预测的模式是否会产生观察到的逆转率，都将允许排除不切实际的模型假设。揭开地幔对地核发电机的影响将使我们能够利用丰富的古地磁记录来了解地球的深层动力学。

Ever since the pioneering work of Glatzmaier et al.1999, it is understood that Earth's mantle exerts critical control on the dynamo action in the liquid iron core. The amount and pattern of core heat loss through the Core-Mantle Boundary (CMB) effects the magnetic field strength, geometry, and dynamics, including its reversal rate. Here we propose to take advantage of recent dramatic progress in mantle convection and dynamo simulations capabilities to investigate this first-order process of core and mantle coupling over a time span of 100 million years, ranging from the enigmatic Cretaceous Normal Superchron (CNS) to present-day. The well-documented increase in reversal rate from only very few reversals during the CNS to about 4 per Myr. today provides important constraints for both dynamo and mantle dynamics. Our mantle convection simulations will exploit state-of-the-art geodynamic data-assimilation techniques through the adjoint method in high resolution models, applying more than 670 million grid points for discretizing Earth's mantle, to retrodict global mantle flow back in time and to track the amplitude and pattern of core heat loss across the CMB. Geologic constraints on past dynamic topography will help to inform the selection of optimal geodynamic modeling parameters employed forthe mantle flow trajectories. Next to isochemical dynamic Earth models in pyrolite composition we will bring new thermo-chemical adjoint techniques to bear, in order to retrodict mantle flow under the assumption of large dynamically isolated mantle domains, in particular the LLSVPs. State-of-the-art dynamo simulations at different parameter combinations will explore the impact of different CMB heat flux pattern on the geodynamo. Whether or not the pattern from the etrodictions will yield the observed reversal rate will allow dismissing unrealistic model assumptions. Unraveling the mantle influences on the core dynamo will enable us to exploit the rich paleomagnetic record for understanding Earth’s deep dynamics.