Modeling the Geomagnetic Field on Million Year Time Scales

百万年时间尺度的地磁场建模

• 批准号: 0337712
• 负责人: Catherine Johnson
• 金额: --
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0337712&HistoricalAwards=false
• 关键词: Modeling; Geomagnetic; Field; Million; Year

The investigators will study long term secular variations of the geomagnetic field using paleomagnetic data from lava flows and marine sediments. Such studies reveal can reveal structures in the time-averaged geomagnetic field and in its variability, which may reflect thermal or compositional geographical heterogeneities on the core-mantle boundary. These heterogeneities may ultimately control the nature of the geodynamo and provide important insight into our understanding of deep-earth processes. Work on this project involves compilation and analysis of large paleomagnetic datasets as well as theoretical developments that will aid in their analysis. The investigators will study the persistence of features in the time-averaged field for the past million years. In addition they will extend global statistical models for paleosecular variations to include anisotropy observed in existing datasets and temporal covariance of a kind that mimics that seen in the power spectrum of paleomagnetic data. They will develop time varying geomagnetic field models for the past million years, and construct a power spectrum for paleomagnetic intensity variations for time periods ranging from hundreds to millions of years. These analyses will allow studies of physical processes that might give rise geomagnetic secular variations on a few kyr to 100 kyr time scales.The work proposed deals with aspects of geomagnetic field behavior that are intimately linked to deep Earth processes (core-mantle interactions, inner core evolution and structure) and, more speculatively, to the influence of orbital and rotational dynamics on the geodynamo. The proposed research will have long-term impact for the magnetics community because the investigators propose systematic electronic archiving of data sets, tools, and products in a community database (MagIC). These will be of use to other researchers in geo/paleomagnetism, and the products that will be archived (images, models, movies) will be of particular use for general research and educational purposes. The research proposed here will provide graduate education and form the core of two PhD theses, as well as providing research experience to undergraduates. Education and outreach efforts will include the development of products to help support future teacher workshops run through the SIO visualization center. The investigators also plan to work in tandem with science teachers at High Tech High school where they are developing a seminar series highlighting local research.

研究人员将利用来自熔岩流和海洋沉积物的古地磁数据研究地磁场的长期长期变化。这些研究表明，可以揭示时间平均地磁场及其变化性的结构，这可能反映了核-幔边界的热或成分地理非均匀性。这些不均匀性可能最终控制地球发电机的性质，并为我们理解地球深部过程提供重要的见解。该项目的工作包括汇编和分析大型古地磁数据集以及有助于分析的理论发展。 研究人员将研究过去百万年中时间平均场特征的持续性。此外，他们将扩展全球统计模型的古长期变化，包括各向异性观察到现有的数据集和时间协方差的一种模仿，在古地磁数据的功率谱。他们将开发过去百万年的时变地磁场模型，并构建从数百年到数百万年的时间段内古地磁强度变化的功率谱。这些分析将使研究物理过程，可能会引起地磁长期变化的几千年至100 kyr的时间scale.The工作提出的交易方面的地磁场的行为密切相关的地球深部过程（核-幔相互作用，内核的演变和结构），更推测，对地球发电机的轨道和旋转动力学的影响。拟议的研究将对磁学社区产生长期影响，因为研究人员建议在社区数据库（MagIC）中对数据集，工具和产品进行系统的电子存档。这些将对地球/古地磁学的其他研究人员有用，存档的产品（图像、模型、电影）将特别用于一般研究和教育目的。这里提出的研究将提供研究生教育，并形成两个博士论文的核心，以及为本科生提供研究经验。 教育和推广工作将包括开发产品，以帮助支持未来通过SIO可视化中心运行的教师研讨会。调查人员还计划与高科技高中的科学教师合作，在那里他们正在开发一个强调当地研究的系列研讨会。