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CAREER: Deformation by surface loading from ocean tides and continental water on a 3-D Earth

职业：3-D 地球上海洋潮汐和大陆水的表面载荷造成的变形

基本信息

批准号：
2144913
负责人：
Hilary Martens
金额：
$ 68.91万
依托单位：
University of Montana
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2027-06-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2144913&HistoricalAwards=false
关键词：
CAREER Deformation surface loading ocean

项目摘要

Circulations of fluids in the oceans, in the atmosphere, and over land cause the shape of the Earth to deform on time scales due to changes in surface pressure. The pattern of deformation depends on the weight and distribution of the fluids as well as on the structural properties of Earth’s interior. Thus, observations and models of Earth deformation caused by repeated cycles of surface loading and unloading can shed light on important Earth-system processes, including mantle dynamics, the water cycle, and changes in climate. For well-known loads, such as the ocean tides, investigations of surface loading can place key constraints on allowable models for the density structure and mechanical behavior of Earth’s crust and mantle, which can advance understanding of mantle convective processes that drive plate tectonics and surface hazards. Furthermore, tracking load-induced Earth deformation allows for the quantification of changes in freshwater storage over the continents, which can aid in drought monitoring and water-resource management. This project aims to advance both observational and computational methods for analyzing how the Earth deforms under the weight of water and air at the surface. Recent studies suggest that the observational precision of state-of-the-art satellite positioning systems, including the Global Positioning System (GPS), may now exceed the predictive capabilities of current Earth-deformation models that commonly assume spherically symmetric Earth structure. Thus, a major objective of this project will be to leverage new advances in computational technologies and geophysical software to investigate the impacts of three-dimensional (3-D) variations in Earth structure (i.e., topography, polar flattening due to rotation, and lateral variations in internal structure) on load-induced Earth deformation. By making predictive models of surface loading more accurate, and by packaging computational tools in a way that the broader scientific community can use with greater ease, this project aims to refine existing models of Earth structure, improve estimates of freshwater storage over the continents, and promote collaborative efforts that drive innovation in geophysics. With computational methods becoming more sophisticated, resources that support and enhance the computational literacy of early-career scientists will become ever more critical to workforce development and sustained innovation. This project will produce a series of computational short courses that can be delivered to students, postdoctoral scholars, and the broader scientific community in flexible formats. This project will also facilitate graduate-undergraduate mentoring and professional-development programs as well as generate open educational resources. A primary objective of this project is to quantify the influence of 3-D variations in solid-Earth structure, including topography and internal contrasts in material properties, on surface displacements caused by ocean tidal loading and continental water loading. This project will analyze data products from Global Navigation Satellite Systems (GNSS) and develop models to predict the response of a 3-D Earth to cycles of surface loading and unloading. Research products will include: (1) sensitivity and resolution analyses that quantify the ability to constrain 3-D Earth structure using GNSS; (2) quantitative assessments of the impacts of 3-D Earth structure on estimates of ocean tidal loading and continental water storage; (3) empirical estimates of load tides from GNSS data; (4) open-source software tools that facilitate tidal analysis and the inversion of geodetic data for Earth structure; and (5) refined models for Earth structure constrained by GNSS observations of load tides.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

由于地表压力的变化，海洋、大气和陆地上的流体循环导致地球的形状在时间尺度上变形。变形模式取决于流体的重量和分布，以及地球内部的结构特性。因此，地表加载和卸载的反复循环造成的地球变形的观测和模型可以揭示重要的地球系统过程，包括地幔动力学、水循环和气候变化。对于众所周知的载荷，如海洋潮汐，表面载荷的调查可以对地壳和地幔的密度结构和力学行为的允许模型施加关键限制，这可以促进对驱动板块构造和表面灾害的地幔对流过程的理解。此外，通过跟踪负荷引起的地球变形，可以量化各大洲淡水储存量的变化，这有助于干旱监测和水资源管理。该项目旨在推进观测和计算方法，以分析地球如何在地表的水和空气的重量下变形。最近的研究表明，包括全球定位系统(GPS)在内的最先进卫星定位系统的观测精度现在可能超过目前通常假定地球结构为球对称的地球变形模型的预测能力。因此，该项目的一个主要目标将是利用计算技术和地球物理软件的新进展来调查地球结构的三维变化(即地形、旋转导致的极地扁平以及内部结构的横向变化)对负载引起的地球变形的影响。通过使地表负荷的预测模型更准确，并通过以更广泛的科学界可以更轻松地使用的方式打包计算工具，该项目旨在改进现有的地球结构模型，改善对大陆淡水储量的估计，并促进推动地球物理创新的合作努力。随着计算方法变得更加复杂，支持和提高职业生涯早期科学家的计算能力的资源将对劳动力发展和持续创新变得更加关键。该项目将制作一系列计算短期课程，可以灵活的形式提供给学生、博士后学者和更广泛的科学界。该项目还将促进研究生-本科生指导和专业发展计划，并产生开放的教育资源。该项目的一个主要目标是量化固体-地球结构的三维变化，包括地形和材料性质的内部对比，对海洋潮汐负荷和大陆水负荷引起的表面位移的影响。该项目将分析全球导航卫星系统(GNSS)的数据产品，并开发模型来预测3-D地球对地表加载和卸载循环的响应。研究产品将包括：(1)利用全球导航卫星系统量化约束三维地球结构的能力的灵敏度和分辨率分析；(2)对三维地球结构对海洋潮汐负荷和大陆水储存估计的影响的定量评估；(3)从全球导航卫星系统数据对负荷潮汐的经验估计；(4)便利地球结构的潮汐分析和大地测量数据反演的开放源码软件工具；以及(5)全球导航卫星系统负载潮汐观测所约束的地球结构精细化模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。