Collaborative Research: Logistically Light Instrument Deployment for Estimation of Antarctic Basal Temperatures and Geothermal Heat Fluxes

标题：用于估计南极基底温度和地热通量的物流轻型仪器部署非技术描述：南极冰盖变量的新观测对于气候记录的钻探地点选择，了解冰动力学如何影响海平面以及调查大陆的地质历史至关重要。温度深度剖面在估计南极洲的基底温度和地热通量方面具有特别重要的意义。除最近的钻探地点外，目前对南极地热热通量知之甚少，是确定基础条件的最大未知因素。然而，目前的物流成本极大地限制了钻井获取温度剖面。我们的长期目标是开发、测试和调试一种比现有方法成本低得多的获取冰川温度剖面的新方法。为此，我们将进行实验室实验和数值模拟，以开发一种使用冰融化探针而不是传统钻探的新方法，将温度测量设备部署到一公里或更深的深度。为了实现这一目的，我们必须保持探头上方的融化冰不完全冻结，这样电缆才能在探头下降时持续不断地被馈送到探头上。这一发展也将为回收熔体探针开辟道路，从而防止对环境的影响和留在现场的设备费用。我们的初步实验和建模将测试我们方法的有效性，并为进一步的现场测试做好准备。技术描述：我们将进行实验室和建模工作(1)，以降低我们的拉曼分布式温度传感（DTS）电缆的熔融探针部署方法的技术风险；(2)开始研制可回收的融冰探测器。具体而言，我们将使用圆柱对称的Stefan问题的数值模拟来指导电缆加热和防冻注入的详细设计，并将通过实验室测试来测试和修改候选设计。我们将测试乙醇填充的熔体孔的长期稳定性，以衡量它们是否适合用于温度测量的可回收熔体探针系统（安装后需要长达数月的热平衡）。我们将通过在我们的实验室实验中使用DTS来测量熔化洞内和邻近冰中的关键温度数据，从而获得拉曼DTS方法的经验。为了解决可恢复性问题，我们将为我们的融冰探针的上端设计和测试一个新的融冰头，并演示通过部分重新冻结的融冰洞向上移动。最后，我们将在同行评审的出版物中发表模型和实验结果，并将在西雅图科学技术博物馆的特别活动中向广大公众展示该项目。这项工作的结果将证明技术准备就绪，以便尽早在较大的冰钻测试设施进行后续项目的测试（预计在本项目完成后不久在威斯康星大学进行），然后在现场进行测试。

Title: Logistically Light Instrument Deployment for Estimation of Antarctic Basal Temperatures and Geothermal Heat FluxesNon-Technical Description: New observations of Antarctic ice sheet variables are essential for drill-site selection for climate records, for understanding how ice dynamics affect sea level, and for investigating the geologic history of the continent. Temperature depth-profiles are of particular current interest for estimating basal temperature and geothermal heat flux in Antarctica. Antarctic geothermal heat flux is presently poorly known except at recent drilling sites, and is the largest unknown in determining basal conditions. However, current logistical costs greatly limit drilling to acquire temperature profiles. Our long-term goal is the development, testing and commissioning of a new means of acquiring englacial temperature profiles at much lower costs than existing methods. To that end, we will undertake laboratory experiments and numerical modeling to develop to a new way to use ice melt probes, rather than traditional drilling, to deploy temperature measurement equipment to depths of a kilometer and greater. To use melt probes for this purpose, we must keep the melted ice above such probes from freezing completely, so that cable can be fed continually down to the probe as it descends. This development will also open the way toward recovering melt probes, so as to prevent environmental impacts and expense of equipment left in the field. Our initial experiments and modeling will test the validity of our approach and make it ready for further testing in the field.Technical Description: We will undertake laboratory and modeling work (1) to reduce the technical risk in our approach to melt-probe deployment of Raman Distributed Temperature Sensing (DTS) cables; and (2) to begin development of a recoverable ice melt probe. Specifically, we will use numerical modeling of the Stefan problem with cylindrical symmetry to guide detailed designs for cable-heating and anti-freeze injection, and will test and revise candidate designs by means of laboratory testing. We will test the long-term stability of ethanol-filled melt holes, to gauge their suitability for recoverable melt probe systems for temperature measurement (where months-long thermal equilibration after installation will be required). We will gain experience with Raman DTS methods by employing DTS to measure critical temperature data in our laboratory experiments, both within the melt hole and in adjacent ice. To address recoverability, we will design and test a new melt head for the upper end of our ice melt probe, and demonstrate upward travel through a partially refrozen melt hole. Finally, we will publish both modeling and experimental results in peer-reviewed publications, and will present the project to a broad public audience in a special event at a Seattle museum of science and technology. The result of this work will be demonstrated technical readiness for testing in a subsequent project at larger ice-drilling test facilities at the earliest opportunity (prospectively, at the University of Wisconsin, following soon after completion of this project) and, following that, in the field.