Current measurements under ice

Current measurements under ice face some challenges not present when measuring current in open water and water free of ice. There is the problem of getting the current meter through a hole in the ice, which limits the horizontal dimensions of the instrument package such as fins that might provide directional stability in open water. Then there is the issue of damage to the sensor from contact with ice in the hole, a problem that is generally less threatening in open water, so for ice deployments protection against this may be required. The small chunks of ice in the hole may interfere with the measurement, certainly a major concern with mechanical sensors, but also an issue with acoustic sensors. Finally, a mooring anchored to the moving ice surface must be tracked for recovery if data are to be only recorded internally. If the data are to be telemetered ashore there must be a data connection to the surface through the mooring line.