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

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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.