Collaborative Research: IPY: POLENET/Greenland: Using Bedrock Geodesy to Constrain Past and Present Day Changes in Greenland's Ice Mass

ABSTRACTBevisOPP-0632320CsathoOPP-0632310Intellectual Focus这是俄亥俄州立大学和纽约州立大学布法罗分校的首席研究人员共同提出的建议。他们将在格陵兰岛建立一个由连续GPS站组成的网络(GNET)，作为美国对国际极地年(IPY)和国际POLENET联盟的贡献的一部分。他们将使用这个网络来绘制与冰后反弹(PGR)相关的稳定垂直速度场，这将为GRACE和任何后续任务提供准确的‘PGR校正’，从而抑制迄今为止基于GRACE估计格陵兰冰量变化的最大不确定性来源。他们打算利用GNET来“衡量”冰块的年度和年际变化，利用地球对地表负荷变化的瞬时弹性响应，获得比Grace更好的空间分辨率。这一方法将通过将年度或季节加载模式(原因)与相邻基岩的同相季节振荡联系起来进行校准和验证。通过这种方式校准了一台‘磅秤’，首席调查人员将能够快速检测和分析任何长期冰增率或损失率的突然增加。与IPY相关：Polenet(极地地球观测网络)是一个由24个国家组成的联盟，将在IPY期间显著提高极地地区的大地、磁场和地震数据的覆盖范围。GNET涉及三个国际伙伴，是整个格陵兰岛POLENET部署的最大组成部分，也是北半球唯一专注于主要冰盖的POLENET组成部分。它将补充北极其他地区的GPS倡议，这些倡议将由12个以上参与POLENET的国家实施。Polenet将克服地球极地地区观测系统稀缺的问题，并将在观测基础设施和在极端环境中部署自主操作的技术能力方面提供遗产。全球定位系统数据和元数据一旦到达联安办事处档案，就将立即向全球科学界提供。POLENET项目将带来在北极和南极运营自主站的新技术的开发。它将促进冰川学家、大地测量学家、地球物理学家、地质学家、气象学家和海洋学家之间在这些学科历史上最全面的合作之一。该项目将把NASA的GRACE项目的重要性提升到一个全新的水平，因为为GRACE提供“PGR校正”将使其成为有史以来开发的用于直接观测冰盖和海洋之间质量转移的最强大的测量系统。GNET将能够探测到格陵兰冰块质量的任何快速增加或减少，特别是在冰盖的临界边缘，以应对气候条件的变化。更广泛地说，了解和监测格陵兰(以及南极)冰盖的行为，是一个具有巨大社会意义的问题。人们普遍认为，西南极或格陵兰冰盖可能崩塌，从而严重损害全球经济，并通过淹没世界各地人口稠密的大片沿海地区，破坏支持数亿人的社会基础设施，这是一种严重的危险。虽然在海平面上升成为严重问题之前扭转全球变暖可能为时已晚，但至关重要的是评估海平面上升可能的严重程度，以及我们各国政府必须应对或缓解它们可能无力阻止的事态发展的时间长短。鉴于这一议程的重要性，我们提议利用联阿援助团的外联专家制定一个外联部分。

ABSTRACTBevisOPP-0632320CsathoOPP-0632310Intellectual Focus. This is a collaborative proposal from Principal Investigators at Ohio State University and SUNY Buffalo. They will construct a network (GNET) of continuous GPS stations in Greenland as part the U.S. contribution to the International Polar Year (IPY) and the international POLENET consortium. They will use this network to map the steady vertical velocity field associated with postglacial rebound (PGR), which will provide GRACE, and any successor missions, with an accurate 'PGR correction', thereby suppressing by far the largest source of uncertainty in GRACE-based estimates of ice mass changes in Greenland. They intend to use GNET to 'weigh' annual and interannual changes in ice mass, obtaining better spatial resolution than GRACE is capable of, using Earth's instantaneous elastic response to surface load changes. This approach will be calibrated and validated by relating annual or seasonal patterns of loading (the cause) with in-phase seasonal oscillations of adjacent bedrock. Having calibrated a 'weighing machine' in this way, the Principal Investigators will be able to quickly detect and analyze any abrupt increases in long terms rates of ice gain or loss.Relevance to IPY: POLENET (Polar Earth Observing Network) is a consortium involving 24 nations that will dramatically improve the coverage in geodetic, magnetic, and seismic data across the polar regions during IPY. GNET, which involves three international partners, constitutes the largest component of a POLENET deployment across Greenland, and is the only POLENET component in the northern hemisphere which is focused on a major ice sheet. It will complement GPS initiatives elsewhere in the Arctic to be carried out by more than 12 nations participating in POLENET. POLENET will overcome the scarcity of observational systems in the Earth's polar regions, and will provide a legacy in observational infrastructure and in the technological capability to deploy autonomous operations in extreme environments. The GPS data and metadata will be made available to the global science community as soon as they reach the UNAVCO archive.Broader Impacts. The POLENET project will bring about the development of new technologies for operating autonomous stations in the Arctic and Antarctic. It will promote one of the most holistic collaborations between glaciologists, geodesists, geophysicists, geologists, meteorologists and oceanographers in the history of these disciplines. This project will leverage NASA's GRACE project to an entirely new level of importance, because providing GRACE with a "PGR correction" will transform it into the single most powerful measurement system ever developed for the direct observation of mass transfer between the ice sheets and the oceans. GNET will be able to detect any rapid acceleration in ice mass gain or loss in Greenland, especially at the critical margins of the ice sheet, in response to changing climatic conditions. Even more broadly, understanding and monitoring the behavior of the Greenland (as well as the Antarctic) ice sheet,is a matter of tremendous societal importance. It is widely understood that there is serious danger that the West Antarctic or Greenland ice sheets could collapse and so seriously damage the global economy, and degrade the social infrastructure supporting hundreds of millions of people, by inundating large swaths of densely inhabited coastal areas worldwide. While it may be too late to reverse global warming before sea level rise becomes seriously problematic, it is crucial to assess both the possible severity of sea level rise, and the amount of time that our governments have to respond to, or mitigate, developments that they may be powerless to prevent. Given the importance of this agenda, we propose to develop an outreach component using UNAVCO's outreach specialists.