Data Types
Each Argo float is identified by a unique identification number called a WMO ID. WMO (World Meteorological Organisation) ID Numbers are assigned to measurement stations and observing platforms to enable researchers to keep track of, and uniquely identify their floats.
Argo floats provide measurements of temperature and salinity of the upper 2000m of the water column at 10 day intervals. These float measurements reveal the detailed structure of the ocean beneath the sea surface. When not profiling, the floats drift with the ocean currents at a particular "parking" depth (usually 1000 m for Australian floats) also enabling estimates of deep current velocity to be obtained.
The figures below show some of the different data types that can be derived from Argo floats. These plots are for Argo float with WMO ID=5901166 which was deployed to the west of Western Australia, offshore from Perth and which has drifted in the Leeuwin Current that flows southwards along the West Australian coast. The first plot shows a time series of salinity with depth and the second plot shows a time series of temperature with depth.
In addition to the measurements of water properties. Argo floats also drift with the currents giving us lagrangian velocity information. The plot below shows the trajectories of two Argo floats initially deployed between Tasmania and Antarctica in the Southern Ocean. These two floats have drifted for several years with the Antarctic Circumpolar Current and have even crossed paths! They are now continuing their drift and are approaching the southeastern Pacific Ocean.
