Ice-Tethered Profiler

Ice-Tethered Profilers (ITPs) are autonomous, freely drifting measurement platforms that record vertical profiles of water mass properties in the ice-covered oceans. The systems are moored on the ice and measure temperature, salinity, and pressure in the upper 800 to 1000 meters of the water column. To conduct the measurements, a sensor package moves vertically along a cable one or more times per day.

The movement along the cable is achieved either by a motorized wheel or by an oil bladder that adjusts buoyancy, similar to a float.

Data is transmitted from the sensor system to the surface unit via electromagnetic induction along the cable. From there, the data, along with position measurements from a GPS receiver, is sent via satellite communication (IRIDIUM), making it accessible to scientists on land on a daily basis.

The collected data can be used, for example, to study changes in the freshwater content of the upper Arctic Ocean, as in the NORTHATLANTIC project.

Together with higher-precision data from ship-based expeditions, the data from these autonomous measurement systems enable year-round scientific analyses of the upper water column, which would not be possible with ship-based measurements alone.

The data from Ice-Tethered Profilers operated by the Woods Hole Oceanographic Institution is available online. The deployment of these autonomous measuring systems is coordinated through the International Arctic Buoy Programme.