Interaction between mass changes of the Antarctic Ice Sheet and solid Earth in Dronning Maud Land, East Antarctica

本项目旨在通过提高空间分辨率的大地GNSS测量，在20多年的时间跨度内确定东南极洲大西洋部分的地壳变形。应估计固体地球对现在和过去冰质量变化的响应，即瞬时弹性响应和冰川均衡调整。更新建议是基于在Dronning Maud Land （DML）西部和中部以及恩德比Land Molodeshnaya地区进行重复GNSS测量的更新计划。在利用卫星重力测定南极冰盖的物质平衡时，冰川均衡调整（GIA）仍然具有最大的不确定性。唯一直接测量GIA效应的方法是在基岩上实现大地GNSS测量。根据目前的调查，南极洲的垂直变形模式并不均匀。DML和恩德比地（Enderby Land），至少在一定程度上，是预计会有相对较小变形信号的地区，但迄今为止只有少数大地测量GNSS站点测量到。申请人小组于1995年在DML发起了运动式的大地测量GNSS测量，并于2007年在恩德比地发起了测量。这些遗址大多位于与海岸平行的山脉中，内陆约100至200公里，以及沿海地区，如希尔马赫绿洲和莫洛德什尼绿洲。考虑到15年以上的时间跨度，重复大地GNSS测量是及时的。我们期望以精确到几毫米/a的精度确定垂直变形率。为此，我们的目标是在使用差分GNSS处理时，详细研究时空相关性对调整变形率和相关不确定性的影响。随后，gnss推断的垂直变形率将作为改进的GIA确定的约束条件。GIA效应将通过两种方式进行估算：首先，卫星测高和重力测量相结合，以经验估算冰-质量平衡和GIA。其次，通过与AWI的合作伙伴密切合作，地球的3D流变结构将被修订，并随后引入GIA预测。将特别注意在计算瞬时弹性变形和GIA时应用流变参数的一致性。因此，我们的目标是为科学界目前正在进行的讨论做出贡献，即如何以更好的方式捕捉地球内部的物理过程，了解其复杂性，并更好地了解GIA所反映的冰质量变化与固体地球之间的相互作用以及相关的海平面变化。

This project aims to determine the deformation of the Earth’s crust in the Atlantic sector of East Antarctica, by geodetic GNSS measurements with improved spatial resolution and over a long time span of partly more than 20 years. The response of the solid Earth to present and past ice-mass changes shall be estimated, namely the instantaneous elastic response and the glacial-isostatic adjustment. The renewal proposal is based on an updated plan to carry out repeated GNSS measurements in western and central Dronning Maud Land (DML) as well as in the region of Molodeshnaya, Enderby Land. Glacial-isostatic adjustment (GIA) still exerts the greatest uncertainty when determining the mass balance of the Antarctic Ice Sheet by satellite gravimetry. The only direct measurement of the GIA effect can be obtained by realizing geodetic GNSS measurements on bedrock. As investigated so far, the vertical deformation pattern is not uniform across Antarctica. DML and, at least to a certain extent, Enderby Land are areas where comparably small deformation signals are expected but measured so far by only a few geodetic GNSS sites. The group of the applicant initiated campaign-style geodetic GNSS measurements in DML in 1995, and in Enderby Land in 2007. Most of these sites are situated in the mountain ranges that run parallel to the coast about 100 to 200 km inland as well as in coastal areas like Schirmacher Oasis and Oasis Molodeshny. Given the long time span of 15 years and more, it is timely to repeat the geodetic GNSS measurements. We expect to determine the vertical deformation rate with an accuracy of down to a few mm/a. For this, we aim to investigate in detail the effect of temporal and spatial correlations on the adjusted deformation rates and associated uncertainties when using the differential GNSS processing. Subsequently, the GNSS-inferred vertical deformation rates will serve as constraints for an improved GIA determination. The GIA effect will be estimated in two ways: First, satellite altimetry and gravimetry will be combined to empirically estimate ice-mass balance and GIA. Second, by close cooperation with partners from AWI, the 3D rheological structure of the Earth will be revised and, subsequently, introduced into GIA predictions. Special attention will be given to improve consistency in applying rheological parameters in the calculation of both the instantaneous elastic deformation and GIA. Thus, we aim to contribute to the currently ongoing discussion within the scientific community on how the physical processes in the Earth’s interior can be captured in a better way, to learn about their complexity, and to gain an improved understanding of the interaction between ice-mass changes and solid Earth that is reflected by GIA and related sea-level change.