Geodetic observation of geodynamic and glaciological processes at the Patagonian Ice Fields

在区域范围内，冰盖、冰场和冰川会以不同的方式因应气候变化而发生大规模变化，影响到宝贵的水资源、局部灾害、全球海平面和固体地球过程。今天，巴塔哥尼亚北部和南部的冰场(NPI和SPI)在范围、体积和质量上都发生了剧烈的变化。然而，对这些变化的量化和解释仍然不确定。冰块的变化与地下固体地球的巨大变形是相互关联的。在SPI观测到的抬升速率是世界上由冰引起的最大速率之一。固体-地球变形的异常大小与该地区特殊的构造和流变环境有关，其特点是智利三重结处的大洋中脊俯冲，巴塔哥尼亚板块窗口的打开，以及极低粘度的热地幔物质的上涌。巴塔哥尼亚负荷变形的模拟--弹性变形和冰川均衡调整(GIA)--面临着特殊的流变学环境、最近冰块变化的不确定性以及有限的观测基础，而不仅仅是地球表面的变形。为了改善这一观测基础，这项建议旨在实现不同的测量活动，这些活动将得到密切协调，以节省成本。首先，我们将与M.Braun(FAU Erlangen-Nürnberg)牵头的一个项目密切合作，利用阿尔弗雷德·韦格纳研究所(AWI)的Polar-5/6飞机实现巴塔哥尼亚冰原的地球物理-冰川飞行。在进行这些飞行活动时，我们将获得对冰面高度、冰体内部分层以及SPI和NPI重力场的航空测量。第二，它的目的是在智利和阿根廷巴塔哥尼亚的现有标记处重复进行全球导航卫星系统大地测量。作为这些观测活动和原始数据处理的结果，我们将获得飞行轨迹、沿飞行剖面的冰面高度以及SPI和NPI的重力扰动的3D坐标。对于分别位于智利的纳塔莱斯港-托雷斯德尔佩因港和SPI以东(阿根廷圣克鲁斯省)的多达35个地点，我们将获得垂直和水平形变率。对于飞行活动和全球导航卫星系统在巴塔哥尼亚南部的实地活动来说，考虑到复杂的天气条件，特别是地面工作，距离远，难以进入测量地点，后勤工作具有挑战性。因此，本提案仅侧重于新数据的获取和随后对原始数据的处理。对所有已获得的观测数据的综合分析和解释将由一个单独的(后续)项目完成。

Regionally in different ways, ice sheets, ice fields and glaciers are subject to mass changes in response to climate change, affecting valuable water resources, local hazards, global sea level and solid-earth processes. Today, the Northern and Southern Patagonian Ice Fields (NPI and SPI) undergo intense changes in extent, volume and mass. Yet, quantification and explanation of these changes remain uncertain. Ice-mass changes are interlinked with a substantial deformation of the underlying solid Earth. Uplift rates observed at the SPI are among the largest ice-induced rates worldwide. The exceptionally high magnitude of solid-earth deformation is related to the peculiar tectonic and rheological setting of the region, characterized by the subduction of a mid-oceanic ridge at the Chile Triple Junction, the opening of the Patagonian slab window and the upwelling of hot mantle material of very low viscosity. The modelling of load deformations in Patagonia – both of elastic deformation and glacial-isostatic adjustment (GIA) – faces the challenges of the peculiar rheological setting, of the uncertainty of recent ice-mass change and of the limited observational basis not only on Earth surface deformation.In order to improve this observational basis, this proposal aims to realise different measurement campaigns which will be closely coordinated in order to economise on costs. First, in close cooperation with a project lead by M. Braun (FAU Erlangen-Nürnberg) we will realize geophysical-glaciological flight campaigns of the Patagonian ice fields using the aircraft Polar-5/6 of Alfred Wegener Institute (AWI). Conducting these flight campaigns we will acquire airborne measurements of ice-surface height, of the internal layering of the ice bodies, and of the gravity field at the SPI and NPI. Second, it is aimed to carry out repeated geodetic GNSS measurements at existing markers both in Chilean and Argentinean Patagonia. As a result of these observation campaigns and the raw data processing we will obtain 3D coordinates of the flight trajectory, ice-surface elevation along the flight profiles, and gravity disturbances for both the SPI and NPI. For up to 35 sites in the region Puerto Natales – Torres del Paine (Chile) and east of the SPI (Provincia Santa Cruz, Argentina), respectively, we will obtain vertical and horizontal deformation rates.The temporal and financial efforts to realize the anticipated measurements are substantial. For both the flight campaigns and the GNSS field campaigns in southern Patagonia logistics are challenging considering complicated weather conditions, and especially for the ground-based works, long distances and difficult access to measurement sites. Thus, this proposal focusses solely on the acquisition of new data and the subsequent processing of the raw data. An integral analysis and interpretation of all acquired observables will be subject to a separate (subsequent) project.