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垂直运动的推断联系起来，在广泛的时间尺度上，从地质到大地测量，后者以非潮汐的趋势分析为代表，重力场的时间变化来自超精确的GRACE模型。非洲南部特别适合进行这一分析，因为它是世界上与地幔有关的一些最活跃的动态抬升区域，几乎没有受到水文变化或其他过程的污染。德国慕尼黑工业大学天文与物理大地测量研究所（IAPG）和德国路德维希-马克西米连斯大学地球物理部（GS-LMU）在这一项目中处于有利地位，因为IAPG几十年来一直致力于重力场高分辨率建模的卫星概念，并且GS-LMU率先建立了高分辨率全球地幔环流模型，能够通过基于伴随方法的复杂流体逆理论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)与固体地球相关的信号能否在重力解中分离？2)在哪个时间段内可以依赖与固体地球相关的重力趋势的线性插值？3)该地区是否存在持续的垂直运动？它与地质观测推断出的该地区新生代隆升脉冲有何关系？利用最复杂的重力处理技术，结合强大的、高分辨率的地幔环流来表示非线性对流信号，将有助于我们区分关于地幔对流在塑造区域构造演化中可能产生的影响的端元假设，即准稳定的、与下地幔相关的流动占主导地位，或者，脉动的、半幕式的上地幔流动突出。

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.