SEMINAR: CWR Presents

Monitoring of the ice shelf and sub-ice shelf ocean temperatures represents an important component towards understanding ice sheet stability and the potential for rapid sea level rise.Continuous monitoring is challenging due to difficult surface access, the difficulties to penetrate through the ice shelf, and the need for the long term operation of non-recoverable sensors.

During November 2011, two instrumented moorings were installed through the Ross Ice Shelf of Antarctica at Windless Bight to develop rapid, light-weight drilling and near-continuous fiber-optic temperature monitoring methods. A combination of ice coring for the upper portion of each shelf borehole, followed by a hot-point drill for penetration into the ocean, was employed.

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 near-continuous in time and depth (1-m interval) observations of ice and ocean temperatures to a depth of almost 800 m beneath the ice-shelf surface. Data received via telemetry to date document the presence of near-freezing waters throughout the cavity during November through January, followed by the influx warmer Ross Sea surface waters reaching approximately 150 m beneath the ice-shelf base during February and March. The cyclic return to isothermal conditions was complete by May.

In this talk, we begin with an overview of DTS physics, followed by a detailed look at the installation methods, instrument package design, mooring cable design,power supply and challenges that arose during the year long deployment.

Following a brief discussion of the data processing tools need to achieve high resolution, we present an analysis of entrance and exit of warm sub-shelf waters and their sources. We close with examples of several related DTS experiments in snow dynamics, aquatic ecosystem restoration and soil moisture monitoring, as well as an overview of the US National Science Foundation's community user facility for DTS.

About the speaker

Dr Scott Tyler is a Foundation Professor of Hydrogeology at the University of Nevada, Reno with appointments in the Department of Geologic Sciences and Engineering and the Department of Civil and Environmental Engineering. He is the director of the National Science Foundation’s Center for Transformative Environmental Monitoring Programs; a community instrument facility for DTS.

He is past editor of Water Resources Research, former chair of the Geologic Society of America’s Hydrogeology Division and incoming chairman of the board for the Consortium of Universities for the Advancement of Hydrologic Sciences.

PS* This seminar is free and open to the public & no RSVP required.

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