Ice Diver Distributed Temperature Sensing

Design, construction and laboratory testing (prior to testing in Madison) of a melt
probe with cabling to enable deployment of Raman DTS, as well as injection of ethanol
at 0 C above the descending probe, in collaboration with Collaborative Research
partners at the University of Nevada - Reno (Scott Tyler, PI) and Oregon State
University (J. Selker, PI). The University of Nevada/OSU focus is on the integration of
the DTS system into the melt probe design to provide both real time feedback on the
thermal condition of the probe, and most importantly, the entire borehole from the ice
surface to the probe. This aspect is critical as the system design relies upon a small
diameter unfroze portion of the borehole to remain open throughout the descent
phase.

Deployment in February 2019 to Madison, WI Ice Drilling Program testing facility,
equipment testing, and return to Seattle (see Supporting Files 1 and 2 for
photographs). The new trials tested our approaches to melt-hole control and probe
recovery in the taller column, as well as cable and cable-tension-management methods
more nearly approximating those needed to work on ice sheets. Following the Madison
field trial, we conducted extensive discussion and review of data and lessons
learned. Post audit analysis of the test indicated weaknesses in the heater designs as
well as the cable feed system, weaknesses that the testing was designed to probe. We
then carried out modifications to the melt probe, changing the heater mountings and
control system and redesigning the DTS fiber termination system to allow for a more
seamless integration of other telemetry and ethanol.

Numerical modeling of melt-hole refreezing with and without injection of anti-freeze,
to understand quantitatively conditions where slush formation in a melt-hole filled with
ethanol/water solution and thus to guide equipment design and experimental
procedures (see Supporting Files 3 and 4 for explanatory figures). This work resulted in
a publication currently under review for a special issue of the Annals of Glaciology.

RAW DTS data can be found here: https://nevada.app.box.com/folder/118092693469

与内华达大学雷诺分校（斯科特·泰勒，首席研究员（Principal Investigator，PI））、俄勒冈州立大学（J·塞尔克，首席研究员（Principal Investigator，PI））的合作研究伙伴携手，完成了一款带缆线的融冰探头的设计、搭建与实验室测试（麦迪逊测试前）。该探头可部署拉曼分布式温度传感器（Raman DTS），并能在下行探头上方注入0℃的乙醇。

内华达大学与俄勒冈州立大学的工作重点为将分布式温度传感器（DTS）系统集成至融冰探头设计中，以实时反馈探头自身的热状态，更关键的是可获取冰面至探头间整个钻孔的热况。该环节至关重要，因为本系统的设计依赖钻孔内一小段未冻结的通道在整个下入阶段保持通畅。

2019年2月，团队将设备部署至美国威斯康星州麦迪逊的冰钻探项目测试设施，完成设备测试后运回西雅图（相关照片见辅助文件1与2）。本次新试验针对更高冰柱环境下的融孔控制与探头回收方案、以及更贴近冰盖作业所需的缆线与缆线张力管理方法进行了验证。

麦迪逊野外试验结束后，团队对试验数据与经验教训进行了全面讨论与复盘。经事后审核分析，试验暴露了加热器设计与缆线馈送系统的缺陷——而本次试验的初衷正是探查此类问题。随后团队对融冰探头进行了改进：调整了加热器安装结构与控制系统，并重新设计了分布式温度传感器光纤终端系统，以实现其他遥测设备与乙醇注入系统更无缝的集成。

团队开展了有无注入防冻剂情况下的融孔再冻结数值模拟，以定量分析乙醇/水溶液填充的融孔内雪浆形成的条件，从而指导设备设计与试验流程（相关说明图见辅助文件3与4）。该项研究成果已投稿至《冰川学年鉴》（Annals of Glaciology）专刊，目前处于审稿阶段。

原始分布式温度传感器数据可通过以下链接获取：https://nevada.app.box.com/folder/118092693469