Reconstructing the Holocene geomagnetic field
Reconstructing the Holocene geomagnetic field
复制标题
DOI：
10.1016/j.epsl.2011.10.031
复制
发表时间：
2011-12-15
影响因子：
5.3
通讯作者：
Holme, Richard
中科院分区：
文献类型：
--
作者：
Korte, Monika;Constable, Catherine;Holme, Richard
了解全新世地球磁场的演变对于理解地核中的地球发电机过程是重要的，对于研究长期的日地关系是必要的，并且可以为考古和地层学应用提供有用的年龄限制。基于古地磁和古地磁数据的连续时变全球磁场模型是这方面的有用工具。我们使用全面的数据汇编和最近完善的建模策略，以产生CALS 10k.1b，第一个时变球谐地磁场模型跨越10千公里。该模型是从自助抽样中获得的平均值，以考虑数据中磁性组件和年龄的不确定性（因此版本号为1b而不是1）。该模型显示较低的空间和时间分辨率比早期版本0-3 ka，特别是旨在提供一个强大的代表性的大规模领域的核幔边界（CMB）。我们讨论了地磁偶极子的演变和变化，全新世磁场形态的CMB所示的新的重建。结果与早期的模型（CALS 3k.3和CALS 3k.4）为0-3 ka，但揭示了一些明显的缺陷，在0-7 ka CALS 7K.2模型之前的3 ka。CALS 10k.1b能够分辨10 ky平均值下两半球CMB处的移动的和结构演化的高纬径向场通量瓣，以及持续的非纬向结构。在赤道澳大利亚-澳大利亚地区的时变结构对平均场的贡献特别引人注目。(C)2011 Elsevier B. V.保留所有权利。
Knowledge of the Holocene evolution of Earth's magnetic field is important for understanding geodynamo processes in the core, is necessary for studying long-term solar-terrestrial relationships, and can provide useful age constraints for archeologicaland stratigraphic applications. Continuous time-varying global field models based on archeo- and paleomagnetic data are useful tools in this regard. We use a comprehensive data compilation and recently refined modelling strategies to produce CALS10k.1b, the first time-varying spherical harmonic geomagnetic field model spanning 10 ky. The model is an average obtained from bootstrap sampling to take account of uncertainties in magnetic components and ages in the data (and hence has version number 1b instead of 1). This model shows less spatial and temporal resolution than earlier versions for 0-3 ka, and particularly aims to provide a robust representation of the large-scale field at the core-mantle boundary (CMB). We discuss the geomagnetic dipole evolution and changes in Holocene magnetic field morphology at the CMB as shown by the new reconstruction. The results are compatible with earlier models (CALS3k.3 and CALS3k.4) for 0-3 ka, but reveal some clear deficiencies in the 0-7 ka CALS7K.2 model prior to 3 ka. CALS10k.1b is able to resolve mobile and structurally-evolving high latitude radial field flux lobes at the CMB in both hemispheres, as well as persistent non-zonal structure, in the 10 ky average. Contributions to the average field from time-varying structures in the equatorial Indonesian-Australian region are particularly striking. (C) 2011 Elsevier B.V. All rights reserved.