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).

该提议旨在实现和解释南部巴塔哥尼亚冰菲尔德（南美最南端）地区的重量观察结果。在申请人进行的先前调查过程中，该地区推断出了异常密集的地壳隆起。这种变形是由固体大地对巴塔哥尼亚冰原的过去和现在的冰质变化的反应引起的。尽管目前对过去变化的持续反应是通过冰川相相调整（GIA）分配的，而当今的冰质变化会导致立即弹性响应。对各自效应的大地观察对于改善区域GIA模型至关重要，通过为固体的流变和气候驱动的冰质量进化提供独特的见解。重复的绝对重量法被证明是一种测量观测技术，适合在许多其他地区成功确定GIA。但是，在巴塔哥尼亚冰场的区域中，尚未开始绝对重力测量。该项目建议在三个现场活动中使用FG5绝对重力计对八个站点的区域网络进行重复观察。随着时间的推移，表面重力变化将从这些观察结果中得出。这些将作为GIA和弹性效应的独立观察，缩小卫星重量表数据（Grace和Grace-Fo任务）与大地GNSS观测结果得出的升高速率之间的差距。观察到的表面重力变化将成为联合解释的基础，该解释既包含申请人已经确定的变形速率和宽限期卫星重量表。该解释将阐明伴随着固体大地变形的质量分布。源自地球内部和快速撤退的冰的质量信号之间的分离将导致区域粘弹性地球模型的大幅改善，以更好地理解流变结构和当今的冰质量变化模式，并具有优于卫星重力的空间分辨率。了解在南部巴塔哥尼亚冰菲尔德地区GIA特殊强度的原因将有助于解释在Amundsen Sea Embayment（West Antarctica）中观察到的更快的升高过程。该项目将受益于当前在阿根廷 - 德国大地测量天文台（AGGO）的BKG FG5-227重力计的协同作用。