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

0rsted 和 Champ 卫星位势观测的极地磁特性和质量动力学

• 批准号: 0338005
• 负责人: Ralph von Frese
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0338005&HistoricalAwards=false
• 关键词: Polar; Magnetic; Properties; Mass; Dynamics

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.

北极和南极是地球上最鲜为人知的地区，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架的联系是现代地球科学的一个基本问题。航空和卫星磁力和重力测量是解决隐藏在巨大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，新的卫星地球位势飞行任务为我们提供了增进对极地区域地壳和次地壳特征的了解的机会。这项工作将分离和模拟南极上空Orsted和CHAMP卫星任务观测中的外部、岩石圈和核心磁场分量。利用先进的谱相关理论，将外场的空间和时间动态分量与静态岩石圈和核心场分量分开。岩石圈和核心磁场分量将使用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。将这些卫星组件与近地表重力场异常结合起来，也将有助于减少在地质解释和模拟异常方面的模糊性。增强的核心场分量将改进极地核心场及其长期变化的模型，以便更好地确定磁力测量数据中的地壳异常。我们还将模拟CHAMP重力观测，以了解与热柱和驱动极地板块构造的其他质量流动区域有关的地壳下密度层的变化。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，极大地加强正在进行的了解航空、海洋和陆地磁力调查的地质意义的努力。提取的极地外场分量的空间和时间变化还将与地面地磁观测站数据中的扰动和来自Orsted、CHAMP、电离层探空仪和其他卫星任务的GPS数据的电离层电子密度分布进行比较。这项分析将有助于更好地了解地球表面外场变化对大约800公里高度的影响，磁层-电离层耦合的结构和动力学，以及极光椭圆形的电离层不规则性，这可能影响导航、通信和极地空间天气模拟。该项目还将支持博士后和研究生教育；促进与意大利罗马的国家地质和火山研究所、俄罗斯圣彼得堡的VNIIOkeangeologia和其他国际机构的伙伴关系；并导致开发用于模拟区域重力、磁力和热效应的新的计算机代码。