Polar Magnetic Properties and Mass Dynamics from 0rsted and Champ Satellite Geopotential Observations

北极和南极是地球上最不为人所知的地区，因为它们地处偏远，环境恶劣。了解它们的起源及其与全球构造格局的联系是现代地球科学的一个基本问题。机载和卫星磁力和重力测量是解决隐藏在巨大的冰雪和海水覆盖下的极地地质问题的主要工具。在过去几年中，新的卫星地势任务提供了机会，以提高我们对极地地区的地壳和地壳下特征的理解。这项工作将在Orsted和CHAMP卫星任务的南极观测中分离和模拟外部、岩石圈和核心磁场成分。利用先进的谱相关理论将外场的时空动态分量与岩石圈和岩心场的静态分量分离开来。岩石圈和地核磁场成分将利用CHAMP重力观测进一步分离。增强的岩石圈成分将对极地地壳的构造性质和演化产生新的见解。将这些卫星分量与近地表位势场异常相结合，也将有助于减少异常地质解释和建模的模糊性。增强的地核场分量将改进极地地核场及其长期变化模型，从而更好地定义磁测数据中的地壳异常。我们还将模拟CHAMP重力观测中与热羽流和其他驱动极地板块构造的质量流区域相关的密度层的地壳下变化。我们的结果将通过提供极地重力、热流和地震调查的地壳和地壳下解释，极大地加强对航空、海洋和陆地磁调查的地质意义的理解。提取的极外场分量的时空变化还将与地表地磁观测数据的扰动以及来自Orsted、CHAMP、Ionosonde和其他卫星任务的GPS数据的电离层电子密度分布进行比较。该分析将提高对地球表面到大约800公里高度的外场变化的影响，磁层-电离层耦合的结构和动力学，以及影响导航、通信和极地空间天气建模的极光椭圆的电离层不规则性的理解。该项目还将支持博士后和研究生教育；促进与意大利罗马国家地质火山研究所、俄罗斯圣彼得堡地质研究所和其他国际机构的伙伴关系；并导致开发新的计算机代码来模拟区域重力、磁场和热效应。

The Arctic and Antarctic are the most poorly known regions of the Earth due to their remoteness and harsh environments. Understanding their origin and connection with the global tectonic framework is a fundamental problem of modern earth science. Airborne and satellite magnetic and gravity surveys are principal tools for resolving the polar geology hidden beneath the vast covers of snow, ice and seawater. In the past several years, new satellite geopotential missions are providing opportunities to improve our understanding of the crustal and subcrustal features of polar regions. This work will isolate and model the external, lithospheric, and core magnetic field components in the Orsted and CHAMP satellite mission observations over the Antarctic. Spatially and temporally dynamic components of the external fields will be separated from the static lithospheric and core field components using advanced spectral correlation theory. The lithospheric and core magnetic field components will be further separated using the CHAMP gravity observations. The enhanced lithospheric components will yield new insights on the tectonic properties and evolution of the polar crust. Integrating these satellite components with near-surface geopotential field anomalies will also help reduce ambiguities in geologically interpreting and modeling the anomalies. The enhanced core field components will result in improved models of the polar core field and its secular variations for better definition of crustal anomalies in magnetic survey data. We will also model the CHAMP gravity observations for subcrustal variations in density layers related to thermal plumes and other regions of mass flow that drive polar plate tectonics. Our results will greatly enhance on-going efforts to understand the geological significance of airborne, marine, and terrestrial magnetic surveys by providing crustal and subcrustal interpretations of polar gravity, heat flow, and seismic surveys. The spatial and temporal variations in the extracted polar external field components will also be compared to disturbances in the surface geomagnetic observatory data and electron density distributions of the ionosphere from the GPS data of the Orsted, CHAMP, Ionosonde, and other satellite missions. The analysis will result in improved understanding of the effects of external field variations at the Earth's surface to altitudes of roughly 800 km, the structures and dynamics of magnetospheric-ionospheric coupling, and ionospheric irregularities of the auroral oval that can affect navigation, communications and polar space weather modeling. This project will also support postdoctoral and graduate student education; foster partnerships with the Istituto Nazionale di Geofisica e Vulcanologia in Rome, Italy, VNIIOkeangeologia in St. Petersburg, Russia, and other international institutions; and lead to the development of new computer codes for modeling regional gravity, magnetic, and thermal effects.