Surface mass redistribution from joint inversion of GPS site displacements, ocean bottom pressure (OBP) models, and GRACE global gravity models (JIGOG)

GPS 站点位移、海底压力 (OBP) 模型和 GRACE 全球重力模型 (JIGOG) 联合反演的表面质量重新分布

• 批准号: 30060709
• 负责人: Professor Dr.-Ing. Reinhard Dietrich
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/30060709?language=en
• 关键词: Surface; mass; redistribution; joint; inversion

In a collaborative effort between TUD-DEOS, AWI and GFZ, we aim at developing a strategy for the joint inversion of time series of GPS site displacements, ocean bottom pressure (OBP) data, and standard and non-standard, short-time GRACE gravity models, into mass transfers. Whereas geoid changes are linked to mass redistributions both directly and indirectly, GPS site displacements respond to mass flux indirectly through loading of the Earth.Previous research has indicated that, when combining monthly GRACE solutions with GPS, GPS could significantly contribute to spherical harmonics of global mass redistribution of up to degree 5, including degree 1. GPS sites are sparse for ocean areas and heterogeneous for continental areas. A joint inversion, accounting for error variance-covariance, site distribution and the individual sensitivities of GPS and GRACE in combination with OBP information, will provide more reliable results on all spatial scales than just combining degree-1 from GPS and higher degrees from GRACE. We plan to optimize the inverse methodology developed by Kusche and Schrama (2005a,b), to develop a complementary regional methodology, to incorporate bottom pressure from numerical ocean models, investigate consistency aspects, and validate results. Because relevant mass variations take place at sub-monthly scales GFZ will additionally contribute with nonstandard short-time (7-10 days) GRACE and GRACE/SLR combined gravity field solutions. A major application will be the determination of variations of the total ocean mass. In conjunction with measured oceanic volume variations we will be able to determine thermal expansion and thus global ocean warming with a much higher accuracy than conventional estimates can provide.

在TUD-DEOS、AWI和GFZ之间的合作努力中，我们的目标是开发一种战略，将GPS站点位移、海底压力(OBP)数据以及标准和非标准的短期Grace重力模型的时间序列联合反演为质量传输。虽然大地水准面的变化直接或间接地与质量再分布有关，但GPS站点的位移通过地球的负载间接地响应质量通量。先前的研究表明，当将每月GRACE解与GPS相结合时，GPS可以显著地贡献全球质量再分布的5阶球谐，包括1阶。GPS站点对于海洋地区是稀疏的，对于大陆地区是不均匀的。联合反演考虑了GPS和GRACE的误差方差-协方差、站点分布和个体敏感性，并结合OBP信息，将在所有空间尺度上提供比仅结合GPS的-1阶和GRACE的更高阶数更可靠的结果。我们计划优化Kusche和Schrama(2005a，b)开发的逆方法，开发一个互补的区域方法，纳入数值海洋模式的海底压力，调查一致性方面，并验证结果。由于相关的质量变化发生在次月尺度上，GFZ还将提供非标准的短时间(7-10天)GRACE和GRACE/SLR组合重力场解。一个主要的应用将是确定总海洋质量的变化。结合测量的海洋体积变化，我们将能够以比传统估计高得多的精度确定热膨胀，从而确定全球海洋变暖。