Determination and interpretation of glacial-isostatic deformations of the Earth's crust in West Greenland

过去和现在的变化，冰的质量和他们的相互作用与地球流变学和全球海洋质量再分配引起复杂的模式的负荷变形的地壳。在西格陵兰岛南部，冰川历史特别复杂，包括全新世晚期的冰川再推进。目前对这一冰川作用历史的了解特别不确定，部分原因是对现今地壳变形的测量覆盖面不够，本项目将通过精确的全球导航卫星系统大地测量确定西格陵兰地壳的变形，将开展实地活动，重新观测1995年建立并于2002年首次重新观测的全球定位系统网络的14个地点。2004年至2010年期间增加到网络中的另外11个站点将被重新观察-大部分是第一次。此外，将在现有的活动站点网络中增加两个连续的全球导航卫星系统站点，除了在数量上扩大以前的测量之外，新的观测将使科学利用具有新的质量。这样，就有可能对冰盖边缘这一部分的地壳变形情况作出前后一致的、以数据为基础的描述，新的全球导航卫星系统观测数据将与申请人小组自1995年以来收集的数据以及补充性的格陵兰全球定位系统网络项目和全球导航卫星系统国际服务处提供的数据一起处理。将使用伯尔尼全球导航卫星系统软件，特别注意长期一致参照系统的应用，对由此产生的坐标变化的分析将考虑垂直分量和水平分量。将特别关注沿着东西向剖面的变形梯度。为了解释观测到的地壳变形，将分别考虑对持续冰量变化的弹性响应和对过去载荷变化（冰川均衡调整，GIA）的（时间线性）粘弹性反应。将根据卫星测高和卫星重力测量等卫星观测得出的现今冰量变化模拟弹性载荷变形，减去弹性部分后，将得出GIA引起的地壳变形估计数。它们将用于验证GIA模型（以及冰川历史模型），并将与跨学科合作伙伴一起纳入进一步的研究。

Past and present changes of ice masses and their interaction with Earth rheology and global oceanic mass redistribution induce complex patterns of load deformations of the Earth crust. In the southern part of West Greenland, the glaciation history is particularly complex, including a glacial re-advance in the late Holocene. Current knowledge of this glaciation history is particularly uncertain, which is partly due to insufficient coverage by measurements of present-day crustal deformation.The present project will determine deformations of the Earth crust in West Greenland by precise geodetic GNSS measurements.Field campaigns will be carried out to re-observe the 14 sites of a GPS network which was established in 1995 and was first re-observed in 2002. Additional 11 sites which have been added to the network between 2004 and 2010 will be re-observed --- mostly for the first time. Moreover, two continuous GNSS sites will be added to the existing network of campaign sites.Beyond a quantitative extension of previous measurements, the new observations will allow for a new quality of scientific exploitation. In this way, a consistent, data-based description of crustal deformations in this sector of the ice sheet margin will become possible.The new GNSS observation data will be processed together with the data gathered since 1995 by the group of the applicants and with data from the complementary GNET (Greenland GPS Network) project and from the IGS (International GNSS Service). The Bernese GNSS Software will be used, with special attention on the application of a long-term consistent reference system.The analysis of the resulting coordinate changes will consider both the vertical component and the horizontal components. Special focus will be put on the gradients of deformation along East-West profiles. For the interpretation of the observed crustal deformations, the elastic response to ongoing ice mass changes and the (temporally linear) visco-elastic reaction to past load changes (glacial isostatic adjustment, GIA) will be considered separately. The elastic load deformation will be modelled based on present-day ice mass changes derived from satellite observations such as satellite altimetry and satellite gravimetry.After subtraction of the elastic component, estimates of GIA-induced crustal deformations will be obtained. They will be used to validate GIA models (and hence models of glaciation history) and will be incorporated in further studies with interdisciplinary partners.