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

在TUD-DEOS、AWI和GFZ之间的合作努力中，我们的目标是制定一项战略，将GPS站点位移、海底压力（OBP）数据以及标准和非标准、短时GRACE重力模型的时间序列联合反演为质量转移。而大地水准面的变化直接和间接地与质量再分布，GPS网站位移响应质量通量间接通过loadingoftheEarth.Previous研究表明，当每月GRACE解决方案与GPS相结合，GPS可以显着有助于球谐全球质量再分布的程度高达5，包括1度。全球定位系统的网站是稀疏的海洋地区和异构的大陆地区。一个联合反演，占误差方差-协方差，网站分布和个人的敏感性的GPS和GRACE结合OBP信息，将提供更可靠的结果，在所有的空间尺度上比只是结合度1从GPS和更高程度的GRACE。我们计划优化Kusche和Schrama（2005 a，B）开发的反演方法，开发一种补充的区域方法，将数值海洋模型的底压纳入其中，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（7-10天）GRACE和GRACE/SLR组合重力场解。一个主要的应用将是确定海洋总质量的变化。结合测量到的海洋体积变化，我们将能够确定热膨胀，从而比传统估计提供更高的准确性全球海洋变暖。

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.