The Gravity Field in Antarctica: Geodetic Modelling and Geophysical Inversion (AntGrav)

南极洲重力场：大地测量建模和地球物理反演 (AntGrav)

• 批准号: 365860590
• 负责人: Professor Dr. Roland Pail
• 金额: --
• 依托单位: British Antarctic Survey
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/365860590?language=en
• 关键词: Gravity; Field; Antarctica; Geodetic; Modelling

The gravity field reflects the mass distribution of the Earth. Thus, it allows studying its inner structure and tectonic evolution. In this respect, it is important to gain precise knowledge of the geometry of specific boundary surfaces respectively surfaces of distinct density contrast such as the topography and the crust-mantle boundary (Mohorovicic discontinuity). In Antarctica, the subglacial topography that is covered by an ice sheet of up to 4,000 m thickness is of special interest. Additionally, the geoid as a distinct equipotential surface serves as a reference surface, for instance, in oceanography (for dynamic ocean topography) and in geodesy (for height systems and a globally unified height datum).For the very first time it will now be possible to study the gravity field in Antarctica on a continental scale and in a homogeneous and consistent way. This is facilitated by the recent availability of a new Antarctic-wide compilation of ground-based gravity data published by an international consortium with one of the applicants being lead author (Scheinert et al., 2016). Thus, we aim to unite the expertise of both applicants in global gravity field modelling based on modern satellite gravity missions such as GRACE and GOCE on the one hand, and in regional gravity field improvement in Antarctica based on terrestrial and near-surface gravity measurements on the other hand. Hence, the main objective of our proposal is to determine a combined, consistent, high-resolution gravity field model of Antarctica. This will be based on a thorough validation and homogenization of the Antarctic terrestrial gravity data and their combination with satellite data. We will develop innovative methods for an optimal combination of all gravity data investigating regional and regionally tailored global approaches taking different properties like accuracy and spectral resolution into account. Using this improved continental-wide gravity field model a further objective is to investigate the lithospheric inversion including density and geometry (subglacial topography, Moho depths). For this, we will make use of additional data like ice thickness measurements from radio echo sounding (RES) and grounding line locations. The inversion of the gravity data will utilize sophisticated methods with different ways of constraining by those additional data. Thus, we aim to contribute to overcoming the deficiencies of our knowledge of subglacial topography and lithospheric structure in Antarctica. Both the methods for combined gravity field modelling and gravity inversion with constraints have to be further developed and adapted to the specific situation in Antarctica.The gravity field model as well as the lithospheric model will be complemented by realistic uncertainty estimates. Finally, the impact of these models on several geoscientific disciplines will be assessed, and their usability will be outlined in a scientific roadmap.

重力场反映了地球的质量分布。因此，它允许研究其内部结构和构造演化。在这方面，重要的是要获得精确的知识的几何形状的特定的边界表面，如地形和壳幔边界（Mohorovicic不连续面）的不同的密度对比的表面。在南极洲，被厚达4 000米的冰盖覆盖的冰下地形特别令人感兴趣。此外，大地水准面作为一个独特的等位面，在海洋学（动态海洋地形学）和大地测量学（高度系统和全球统一的高度基准）等方面可作为一个参考面，现在第一次有可能在大陆尺度上以均匀一致的方式研究南极洲的重力场。最近，一个国际财团出版了一份新的基于地面重力数据的全舌形图汇编，其中一名申请人是第一作者，这为这项工作提供了便利（Scheinert等人，2016年）。因此，我们的目标是一方面结合申请人在基于GRACE和GOCE等现代卫星重力任务的全球重力场建模方面的专业知识，另一方面结合申请人在基于陆地和近地表重力测量的南极洲区域重力场改善方面的专业知识。因此，我们建议的主要目标是确定一个综合的、一致的、高分辨率的南极重力场模型。这将以彻底验证和统一南极陆地重力数据及其与卫星数据相结合为基础。我们将开发创新方法，以优化所有重力数据的组合，调查区域和区域定制的全球方法，同时考虑到精度和光谱分辨率等不同属性。利用这个改进的全大陆重力场模型，进一步的目标是研究岩石圈反演，包括密度和几何形状（冰下地形，莫霍面深度）。为此，我们将利用额外的数据，如无线电回声探测（RES）和接地线位置的冰厚度测量。重力数据的反演将利用复杂的方法，以不同方式受这些额外数据的约束。因此，我们的目标是帮助克服我们的知识在南极洲冰下地形和岩石圈结构的不足之处。必须进一步发展重力场综合建模方法和有约束条件的重力反演方法，使之适合南极洲的具体情况，重力场模型和岩石圈模型将得到现实的不确定性估计的补充。最后，将评估这些模型对几个地球科学学科的影响，并在科学路线图中概述其可用性。