Ice flow dynamics, subglacial hydrology and long-term mass balanceat Lake Vostok from the combination of geodetic GNSS observationsand radio-echo sounding

结合大地测量 GNSS 观测和无线电回波探测，了解沃斯托克湖的冰流动力学、冰下水文学和长期质量平衡

• 批准号: 315382723
• 负责人: Dr.-Ing. Mirko Scheinert
• 金额: --
• 依托单位: Polar Marine Geosurvey Expedition
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/315382723?language=en
• 关键词: Ice; flow; dynamics; subglacial; hydrology

This proposal aims at a focused analysis, interpretation and publication of a unique set of geodetic and geophysical in-situobservations in the region of subglacial Lake Vostok, central East Antarctica. These data have been obtained by the applicant and his cooperation partner during nine field expeditions since 2001 up to now. Based on repeated satellite positioning on surface markers the velocity and direction of ice flow across the subglacial lake shall be investigated. The particular conditions in this region limit the applicability of remote sensing techniques and ice-dynamic modelling and make geodetic insitu observations the most reliable source of information. Special attention will be paid to the transition from grounded to floating ice across the lake's shore where preliminary observational results contradict current theoretical considerations. Furthermore, the variability of ice flow in the Lake Vostok region over climatic timescales shall be constrained by a combination of geodetic observations at the surface with the geometry of internal ice layers. In addition, different geodetic techniques shall be combined to separate and quantify the contributions of local ice-mass balance, water volume changes and water movements within the subglacial lake to observable height changes. The largest subglacial lake on Earth represents a particularly promising target for the geodetic determination of ice-flow velocities and height changes. These observations allow insights into the complex interactions between ice, subglacial water and bedrock and interpretations regarding different processes within the lake. Moreover, observational constraints on thepresent and past ice-flow regime are crucial for the interpretation of the ice core retrieved at Vostok station. The results of this project shall be combined in a time-integrating model for the Vostok flowline that determines where ice samples of the core of a certain age were formed. This will contribute to the improvement of the multidisciplinary interpretation of the Vostok ice core that is relevant not only for the understanding of the Lake Vostok system, but also for research on continental and global scales. Although the emphasis is given on the utilization of existing data, the fieldwork shall be continued throughout the project duration to ensure the continuity of the geodetic monitoring. This is a cooperation project with Dr. Sergey V. Popov (PMGE, St. Petersburg) in the frame of the MoU between DFG and the Russian Foundation of Basic Research (RFBR).

该提案旨在对东南极洲中部沃斯托克冰下湖地区的一组独特的大地测量和地球物理现场观测进行重点分析、解释和发布。这些数据是申请人及其合作伙伴自2001年至今进行的9次野外考察中获得的。基于表面标记上的重复卫星定位，应调查冰下湖冰流的速度和方向。该地区的特殊条件限制了遥感技术和冰动力模型的适用性，并使大地测量原位观测成为最可靠的信息来源。将特别关注湖岸从接地冰到浮冰的转变，其中初步观测结果与当前的理论考虑相矛盾。此外，沃斯托克湖地区冰流在气候时间尺度上的变化应受到表面大地测量与内部冰层几何形状相结合的限制。此外，应结合不同的大地测量技术来分离和量化当地冰块平衡、水量变化和冰下湖内水运动对可观测高度变化的贡献。地球上最大的冰下湖是大地测量冰流速度和高度变化的一个特别有前途的目标。这些观测结果使我们能够深入了解冰、冰下水和基岩之间复杂的相互作用，并对湖内的不同过程进行解释。此外，对当前和过去冰流状况的观测限制对于解释东方站取回的冰芯至关重要。该项目的结果应合并到东方流线的时间积分模型中，该模型确定特定年龄的岩心冰样本的形成位置。这将有助于改进对东方冰芯的多学科解释，这不仅与了解东方湖系统相关，而且与大陆和全球尺度的研究相关。虽然重点是利用现有数据，但在整个项目期间仍应继续进行实地工作，以确保大地测量的连续性。这是 DFG 与俄罗斯基础研究基金会 (RFBR) 之间谅解备忘录框架内与 Sergey V. Popov 博士（PMGE，圣彼得堡）的合作项目。