Gravimetric determination of the solid-earth response to ice-mass changes in southern Patagonia

巴塔哥尼亚南部固体地球对冰块变化响应的重力测定

• 批准号: 426109121
• 负责人: Dr.-Ing. Axel Rülke
• 金额: --
• 依托单位: Bundesamt für Kartographie und Geodäsie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426109121?language=en
• 关键词: Gravimetric; determination; solid; earth; response

The proposal aims at the realization and interpretation of gravimetric observations in the region of the Southern Patagonian Icefield (southernmost South America). In the course of previous investigations conducted by the applicants an exceptionally intensive crustal uplift was inferred in this region. This deformation is caused by the response of the solid Earth to past and present ice-mass changes of the Patagonian icefields. Whereas the presently ongoing response to past changes is assigned by glacial-isostatic adjustment (GIA), present-day ice-mass changes cause an immediate elastic response. Geodetic observations of the respective effects are crucial to improve regional GIA models by providing unique insights into both the rheology of the solid Earth and the climatically driven ice-mass evolution. Repeated absolute gravimetry was proven to be a geodetic observation technique suitable for a successful determination of GIA in many other regions. However, in the region of the Patagonian icefields absolute gravity measurements have not been initiated yet. The project proposes to carry out a repeated observation of a regional network of eight sites using a FG5 absolute gravity meter during three field campaigns. Surface gravity changes over time will be derived from these observations. These will serve as an independent observable of GIA and elastic effects, closing a gap between satellite gravimetry data (GRACE and GRACE-FO missions) and the uplift rates derived by geodetic GNSS observations. The observed surface gravity changes will form the basis for a joint interpretation incorporating both the deformation rates already determined by the applicants and GRACE-FO satellite gravimetry. The interpretation will shed light on the mass distributions that accompany the deformation of the solid Earth. The separation between mass signals originating from the interior of the Earth and from the rapidly retreating ice will result in a substantial improvement of regional visco-elastic Earth models, in a better understanding of the rheological structure and of the present-day ice-mass change pattern with a spatial resolution superior to satellite gravimetry. Understanding the causes for the exceptional intensity of GIA in the region of the Southern Patagonian Icefield will help to also explain even faster uplift processes observed in the Amundsen Sea Embayment (West Antarctica). The project will benefit from the synergy with the current presence of BKG's FG5-227 gravity meter at the Argentine-German Geodetic Observatory (AGGO).

该提案旨在实现和解释南巴塔哥尼亚冰原地区（南美洲最南端）的重力观测。在申请人先前进行的调查过程中，推断该区域有异常强烈的地壳隆起。这种变形是由固体地球对巴塔哥尼亚冰原过去和现在的冰量变化的反应造成的。而目前正在进行的响应过去的变化是由冰川均衡调整（GIA），现今的冰量变化导致即时的弹性响应。大地测量观测的各自的影响是至关重要的，以改善区域GIA模型，提供独特的见解，固体地球的流变学和气候驱动的冰块演变。经证明，重复绝对重力测量是一种大地测量观测技术，适用于成功确定许多其他区域的GIA。然而，在巴塔哥尼亚冰原地区，绝对重力测量尚未开始。该项目拟在三次实地活动中使用FG 5绝对重力仪对一个由八个地点组成的区域网络进行重复观测。地表重力随时间的变化将从这些观测中得出。这些将作为全球影响评估和弹性效应的独立观测点，缩小卫星重力测量数据（GRACE和GRACE-FO任务）与全球导航卫星系统大地测量观测得出的隆起率之间的差距。观测到的地面重力变化将构成结合申请人已经确定的变形率和GRACE-FO卫星重力测量进行联合解释的基础。解释将阐明伴随固体地球变形的质量分布。将来自地球内部的质量信号与来自迅速消退的冰的质量信号分开，将大大改进区域粘弹性地球模型，更好地了解流变结构和当今冰质量变化模式，其空间分辨率上级优于卫星重力测量。了解南巴塔哥尼亚冰原地区GIA异常强度的原因也将有助于解释在阿蒙森海湾（西南极洲）观察到的更快的隆起过程。该项目将受益于与阿根廷-德国大地测量天文台（AGGO）目前BKG的FG 5 -227重力仪的协同作用。