Collaborative Research: Toward Dense Observation of Geothermal Fluxes in Antarctica Via Logistically Light Instrument Deployment

合作研究：通过后勤轻型仪器部署对南极洲地热通量进行密集观测

• 批准号: 1745049
• 负责人: Scott Tyler
• 金额: $ 3.24万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-15 至 2020-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1745049&HistoricalAwards=false
• 关键词: Collaborative; Research; Toward; Dense; Observation

Nontechnical AbstractStudies in Antarctica are, at present, severely limited by the costs of placing measurement instruments within and beneath thousands of meters of ice. Our aim is to enable dense, widespread measurement-networks by advancing development of low-cost ice melt probe technology to deploy instruments. Ice melt probes use electrical energy to descend through thick ice with little support structure on the ice surface. We are extending previous technology by using anti-freeze to maintain a partially open melt-hole above a descending probe, deploying as we go a new a new fiber-optic technology to measure ice temperature. Ice temperature measurements will reveal spatial patterns of heat welling up from the Earth beneath the ice, which in turn will contribute greatly to finding ancient ice that contains global climate records, and to understanding how ice flow may raise sea levels. Our immediate objective in this 1-year project is to test and refine our anti-freeze-based method in a 15 meter-tall ice column at the University of Wisconsin, so as to reduce technical risk in future field tests. Technical AbstractThe overarching aim of our development is to enable widespread, spatially dense deployments of instruments within and beneath the Antarctic Ice Sheet for a variety of investigations, beginning with observations of basal temperature and geothermal flux at the base of the ice sheet. Dense, widespread deployment requires logistical costs far below current costs for ice drilling and coring. Our approach is to extend ice melt probe technology (which is inherently light, logistically) to allow the progressive deployment of cable for Distributed Temperature Sensing (DTS) from the ice surface as the probe descends, without greatly increasing logistical costs. Our extension is based on arresting refreezing of the melt-hole above the probe (at a diameter a few times the cable diameter) by injecting anti-freeze - specifically, ethanol at temperature near 0C - a few meters above the probe during descent. After thermal equilibration of the liquid ethanol/water column with the ice, DTS measurements yield the depth-profile of ice sheet temperature, from which basal temperature and (over frozen beds) geothermal flux can be inferred. We have carried out initial trials of our approach in a cold-room laboratory, but field work based only on such small-scale tests may still involve unnecessary risk. We therefore propose further testing at a facility of the Ice Drilling Design and Operations (IDDO) facility in Madison, WI. The new trials will test our approaches to melt-hole control and probe recovery in the taller column, will test cable and cable-tension-management methods more nearly approximating those needed to work on ice sheets, and will demonstrate the Distributed Temperature Sensing in its field configuration.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

目前，南极的非技术抽象研究受到将测量工具放置在数千米冰内和下方的成本的严重限制。我们的目的是通过推进低成本冰融化探针技术来部署工具来实现密集，广泛的测量网络。冰融化的探针使用电能通过厚冰下降，而冰表面几乎没有支撑结构。我们通过使用抗冻结来维持降落探针上方部分开放的熔体孔来扩展以前的技术，并在我们进行新的A新纤维技术技术以测量冰温时部署。冰温测量结果将揭示从冰下的地球上扬起热的空间模式，这反过来将极大地促进找到包含全球气候记录的古老冰，并了解冰流如何提高海平面。 我们在这个为期1年的项目中的直接目标是在威斯康星大学的15米高冰柱中测试和完善我们的基于抗冻的方法，以降低未来现场测试中的技术风险。 技术摘要我们的发展的总体目的是使南极冰盖内部和下方的仪器在空间上进行广泛，密集的部署，以进行各种研究，从冰盖底部的基础温度和地热通量的观察开始。密集的，广泛的部署需要后勤成本远低于冰钻和加油的当前成本。我们的方法是扩展冰融化的探针技术（从逻辑上讲，这是固有的，它本质上是光线的），以便在探针下降时从冰层进行分布式温度传感（DTS）进行逐步部署，而不会大大增加后勤成本。我们的延伸是基于在探头上方（直径几倍）上方的熔体孔进行重新冻结，该延伸是通过注射抗冻结的抗冰冻 - 特别是在温度接近0c的乙醇 - 下降时探针以上几米以上几米。在将液态乙醇/水柱与冰的热量平衡之后，DTS测量结果产生了冰盖温度的深度，从中可以推断出基础温度和（在冷冻床上）地热通量。我们已经在冷室实验室中对我们的方法进行了初步试验，但是仅基于此类小规模测试的现场工作仍可能涉及不必要的风险。因此，我们建议在威斯康星州麦迪逊市的冰钻设计和操作（IDDO）设施的设施进行进一步的测试。新试验将测试我们在较高的列中融化孔控制和探测恢复的方法，将更接近近似于在冰盖上工作的电缆和电缆张紧管理方法，并将证明其现场配置中的分布式温度传感。该奖项反映了NSF的法定任务，并通过评估范围来审查概念的支持，并通过评估范围进行了评估。