Float (Profiling)

A profiling float is an autonomous instrument that cycles vertically through the water column on a fixed schedule, drifting at a set depth between profiles and reporting by satellite, the design behind the Argo array. The float changes buoyancy by pumping oil between an internal reservoir and an external bladder: it parks near 1000 dbar, descends to about 2000 dbar at the start of each cycle, then ascends while a CTD samples temperature and salinity. A full 10-day cycle repeats more than 200 times over a five-year life. Position fixes during the surface interval give a deep displacement velocity at park depth.