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Polar Profiling Floats: Technology

The Polar Profiling Floats have a hard polyurethane patch antenna capable of receiving GPS information and transmitting the data via Iridium and withstand interaction with hard sea ice. The stability disks were removed to streamline the body to minimize the risk of getting stuck to sea ice. The conductivity-temperature probe is made by Seabird and samples at 1 Hz with onboard internal processing to compute salinity from conductivity, temperature and pressure.

The main modification was in the software enabling the floats to repeatedly probe the underside of the ice cover for open water (
see animation). The floats cycles between the surface (or underside of the ice) and 50 m repeatedly. It waits at 50 m for a pre-defined period in order to make sure the ice is displaced relative to the float before it tries to find open water again.

The floats were ballasted and programmed to make one ~900-m deep profile every week and drift at the core of the Atlantic Layer at 300 m (so-called parking depth) between profiles. With current battery packs the estimated mission length is 3-4 years.
Float schematic