Instruments and Methods Using distributed temperature sensors to monitor an Antarctic ice shelf and sub-ice-shelf cavity

Monitoring of ice-shelf and sub-ice-shelf ocean temperatures represents an important component in understanding ice-sheet stability. Continuous monitoring is challenging due to difficult surface access, difficulties in penetrating the ice shelf, and the need for long-term operation of nonrecoverable sensors. We aim to develop rapid lightweight drilling and near-continuous fiber-optic temperature-monitoring methods to meet these challenges. During November 2011, two instrumented moorings were installed within and below the McMurdo Ice Shelf (a sub-region of the Ross Ice Shelf, Antarctica) at Windless Bight. We used a combination of ice coring for the upper portion of each shelf borehole and hot-point drilling for penetration into the ocean. The boreholes provided temporary access to the ice-shelf cavity, into which distributed temperature sensing (DTS) fiber-optic cables and conventional pressure/temperature transducers were installed. The DTS moorings provided nearcontinuous (in time and depth) observations of ice and ocean temperatures to a depth of almost 800 m beneath the ice-shelf surface. Data received document the presence of near-freezing water throughout the cavity from November through January, followed by an influx of warmer water reaching 150 m beneath the ice-shelf base during February and March. The observations demonstrate prospects for achieving much higher spatial sampling of temperature than more conventional oceanographic moorings.

Raw project data is available by contacting [e-mail]

对冰架及冰下海洋温度的监测是理解冰盖稳定性不可或缺的重要环节。鉴于地表接入难度、穿透冰架的挑战以及长期运行不可回收传感器的需求，持续的监测工作颇具挑战性。本研究旨在开发快速轻便的钻探技术与近乎连续的光纤温度监测方法，以应对上述挑战。在2011年11月，我们于麦克默多冰架（罗斯冰架的次级区域，位于南极洲）的无风湾区域，安装了两套装备有仪器的系泊浮标，位于冰架内部及下方。对于每个冰架钻孔的上部，我们采用了冰芯钻探技术，而对于穿透至海洋的部分，则采用了热点钻探技术。这些钻孔提供了临时通道进入冰架内部空洞，并在其中安装了分布式温度传感（DTS）光纤电缆和传统的压力/温度传感器。DTS系泊浮标提供了几乎连续（在时间和深度上）的冰与海洋温度观测，观测深度可达冰架表面以下近800米。收集到的数据记录了从11月到1月整个空洞中近冰点水的存在，随后在2月和3月期间，温暖的水流涌入，深度达到冰架底部以下150米。这些观测结果展示了相较于传统海洋学系泊浮标，实现更高空间温度采样率的潜力。

原始项目数据可通过联系[e-mail]获取。