Determination of current geoid trends related to deep Earth processes in the South Atlantic region

我们建议将南大西洋地区从地质到大地测量的大范围时间尺度上的垂直运动的推断联系起来，后者由来自超精密GRACE模型的重力场的非潮汐时间变化的趋势分析来表示。尤其是非洲南部，是世界上与地幔相关的动态隆起最活跃的地区，几乎没有受到水文变化或其他过程的污染。图明钦天文和物理大地测量研究所(IAPG)和路德维希-马克西米利安大学(GS-LMU)的地球物理系(GS-LMU)非常适合这一项目，因为IAPG几十年来一直致力于卫星概念的研究，以高分辨率模拟重力场。GS-LMU开创了高分辨率的全球地幔环流模型，能够通过基于伴随方法的复杂的流体逆理论来推断过去的地幔流动和结构。我们希望解决的关键问题包括：1)与固体地球有关的信号能否在重力解中分离？2)在哪些时间段可以依赖于与固体地球有关的重力趋势的线性内插？3)该地区是否存在持续的垂直运动，以及它与从地质观测中推断的该地区的新生代隆起脉冲有何关系？使用最先进的重力处理技术，结合强大的高分辨率地幔环流代表非线性对流信号将有助于我们区分关于地幔对流在塑造区域构造演化中的作用的端员假说，即以准稳定的下地幔相关流动为主，或以脉动的半幕式上地幔流动为主。

We propose to link inferences of vertical motion in the South Atlantic region over a wide range of time scales, from geologic to geodetic, the latter represented by trend analyses of non-tidal, temporal variations in the gravity field derived from ultra-precise GRACE models. The southern part of Africa, in particular, is uniquely suited for this analysis, being a region with some of the most active mantle related dynamic uplift world-wide, with little contamination from hydrologic variability or other processes.The Institute for Astronomical and Physical Geodesy (IAPG) of TU München and the Geophysics Section of Ludwig-Maximilians-University (GS-LMU) are well positioned for this project, as IAPG has been working on satellite concepts for the high resolution modeling of the gravity field for many decades, and GS-LMU has pioneered high resolution global mantle circulation models capable of inferring past mantle flow and structure through sophisticated fluid inverse theory based on the adjoint method.Key questions we wish to address include:1) Can solid Earth related signals be separated in gravity solutions?2) Over which time periods may one rely on a linear interpolation of solid Earth related gravity trends?3) Is there ongoing vertical motion in the region and how does it relate to Cenozoic uplift pulses that have been inferred for the region from geologic observations?The use of the most sophisticated gravity processing techniques, combined with powerful, high resolution mantle circulation to represent non-linear convection signals will help us to distinguish end-member hypotheses on the effect that mantle convection may have in shaping the regional tectonic evolution, namely a dominance of quasi-steady, lower-mantle related flow or, alternatively, a prominence of pulsating, semi-episodic upper mantle flow.