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

该项目旨在通过提高空间分辨率的大地全球导航卫星系统测量，在长达20多年的时间跨度内确定东南极大西洋地区的地壳形变。应估计固体地球对现在和过去冰块变化的响应，即瞬时弹性响应和冰川均衡调整。续签建议的依据是一项最新计划，即在Dronning Maud Land(DML)西部和中部以及Enderby Land的Molodeshnaya地区重复进行全球导航卫星系统测量。在利用卫星重力测量确定南极冰盖物质平衡时，冰川均衡平差(GIA)仍然是最大的不确定性。GIA效应的唯一直接测量方法是在基岩上实现GNSS大地测量。到目前为止，整个南极洲的垂直形变模式并不统一。DML和至少在一定程度上的Enderby陆地预计会有相对较小的形变信号，但到目前为止只有几个大地测量全球导航卫星系统站点测量到了这些信号。申请者小组于1995年在DML发起了运动式全球导航卫星系统大地测量，并于2007年在Enderby陆地启动了大地测量。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，以及希尔马赫绿洲和绿洲莫洛德希尼等沿海地区。鉴于时间跨度长达15年和更长时间，重复进行全球导航卫星系统大地测量是及时的。我们预计将以几毫米/年的精度确定垂直形变速率。为此，我们的目标是详细调查时间和空间相关性对调整后的形变速率的影响以及使用差分GNSS处理时相关的不确定性。随后，全球导航卫星系统推断的垂直形变率将成为改进全球定位系统确定的约束条件。GIA效应将通过两种方式估计：首先，将卫星测高和重力测量结合起来，经验地估计冰块平衡和GIA。其次，通过与AWI的合作伙伴的密切合作，地球的3D流变结构将被修订，并随后被引入GIA预测。在计算瞬时弹性变形和GIA时，将特别注意提高应用流变参数的一致性。因此，我们的目标是促进科学界目前正在进行的关于如何以更好的方式捕捉地球内部的物理过程的讨论，了解它们的复杂性，并更好地理解GIA和相关的海平面变化所反映的冰块变化和固体地球之间的相互作用。

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.