EAR-PF: Separating Regional from Global Influences on the Paleomagnetic Record

Leah Ziegler博士获得了美国国家科学基金会地球科学博士后奖学金，将在俄勒冈州立大学开展一项研究和教育计划。她将研究几十万年来海洋沉积物中记录的地球磁场强度的变化。这项研究将侧重于使用时间序列分析、统计和反向建模来评估从数十个不同的沉积物岩芯获得的数据的区域间和区域内的一致性。磁场强度的模型将使用全球区域聚集的数据来建立，这些不同的区域模型将相互比较，并与全球参考模型进行比较。此外，她将量化地理上相距较近和相距较远的各个核心之间的相关性，以测试相关性和地理分离之间是否存在关系。该项目的首要目标是确定在很长的时间尺度上的全球和区域实地特征，并确定区域尺度的特征(更难分辨)是否可以在数据源固有的噪声之上观察到。地球的磁场是不断变化的：强度、小尺度形状和极点位置。虽然磁场近似为偶极场，但它有许多复杂性和偏离这一普遍情况的偏差。一些特定的非偶极子特征可能会持续数百年或数千年，而另一些则只持续几年。从卫星和天文台的测量中可以很容易地观察到今天磁场的全部细节。然而，通过仔细分析来自磁化沉积物的越来越多的数据，恢复古代磁场的细节现在才变得可行。这项研究提供了一个框架，用于理解我们如何能够很好地从这个嘈杂但信息丰富的数据源中解决现场复杂性。在广泛的环境应用中，沉积物中场强的特征起伏经常被用作这些沉积物的年代学工具，其中典型的偶极子场近似有助于年代学的不准确。这项研究将在这些应用中带来更好的时间精度和误差界。对这项工作中产生的古代磁场的更好的理解也将导致对最终产生磁场的地球深处过程的新的洞察。除了她的研究，这位研究员还将通过各种既定的K-12外联计划积极参与俄亥俄州立大学的教育和外联工作。此外，她还将在俄亥俄州立大学合作教授一门本科生水平的课程--“地球磁学”。

Dr. Leah Ziegler has been granted an NSF Earth Sciences postdoctoral fellowship to carry out a research and education plan at Oregon State University. She will investigate the changing strength of the Earth's magnetic field, as recorded in marine sediments over hundreds of thousands of years. This study will focus on using time series analysis, statistics, and inverse modeling to assess the interregional and intraregional consistency of data taken from dozens of separate sediment cores. Models of magnetic field strength will be made using data clustered regionally on the globe, and these different regional models will be compared with each other and with a global reference model. Additionally, she will quantify the correlation between individual cores which are geographically close together and which are geographically far apart, to test if there is a relationship between correlation and geographic separation. The overarching goal of this project is to identify global and regional field features on very long timescales, and to determine if the regional-scale features (which are more difficult to resolve) are observable above the noise which is inherent to the data source. The Earth's magnetic field is ever-changing: in strength, small scale shape, and pole location. Although the magnetic field is approximately a dipole field, it has many complexities and deviations from this generalization. Some specific non-dipole features may last hundreds or thousands of years, while others last only a few years. The full detail of today's field is readily observable from satellite and observatory measurements. However, recovering details of the ancient magnetic field is only now becoming feasible through careful analyses of growing amounts of data from magnetized sediments. This study provides a framework for understanding how well we can resolve field complexities from this noisy - yet informative - data source. The characteristic ups and downs in field strength seen in sediments often serve as a chronology tool for those sediments in a wide range of environmental applications, where the typical dipole field approximation contributes to chronological inaccuracies. This study will lead to better chronological accuracy and error bounds in these applications. The improved understanding of the ancient magnetic field produced in this work will also lead to new insights into the deep earth processes that ultimately give rise to the magnetic field. In addition to her research, the fellow will be active in education and outreach at OSU through a variety of established K-12 outreach programs. She will additionally co-teach an undergraduate level course on "Earth's Magnetism" at OSU.