Andreas Muenchow, professor at the School of Marine Science and Policy at the University of Delaware, deployed three Tilt Current Meters (TCM-1) below "land-fast" sea ice in the Wolstenholme Fjord in Greenland in spring 2017. Land-fast sea ice is ice that is attached or "fastened" to the shore and is essentially a floating extension of the land. The Wolstenholme fjord is covered by ice during the spring, and thus provides a stable platform from which to test, deploy, and recover a range of oceanographic sensors systems via snowmobiles during day-light hours when air temperatures are generally above a -25°C. Ocean currents and temperatures in Wolstenholme Fjord were profiled about 0.05 meter below the sea ice at three mooring locations in March and April of 2017.
The TCMs used inversion kits so that the meters sink (rather than float) and hang below their attachment point. The meters were installed through a drilled 2-inch diameter hole and then attached to a 1.9-inch diameter wooden pole. The pole extended just below the underside of the sea ice. "Ocean currents were estimated from the drag on a pendulum [TCM] attached to the sea ice that measured accelerations and magnetic field strength vectors in the all three spatial dimensions", Muenchow noted, "It is a promising new and simple technology that we successfully put to the test".
The use of the TCM's were part of the larger study to design and develop an integrated underwater acoustic sensor network for ice-covered seas, funded by the National Science Foundation, Office of Polar Programs. "Such a network holds the promise to revolutionize under-ice ocean sampling in polar regions", stated Muenchow.
For more information and links to the research: