Instrumentation
All Argo floats work on the same principles: a battery pack and motor drives oil from inside the float housing to outside in a bladder, changing the float volume and thus its density relative to the surrounding seawater. This allows it to profile up and down through the water collumn.
The Argo float has revolutionised our understanding of the physics of the oceans. Since its inception, it has been providing more information on the physical structure of the upper ocean than the rest of the observing system put together. It has the added advantage that the floats can travel to remote regions of the world ocean, previously difficult to reach by other methods such as research cruises.
A typical Argo float mission is to profile from 2000m depth to the surface every 10 days.The floats drift at 1000m.
Each float has a satellite antenna. When the float reaches the surface, its position and profile data of temperature salinity and pressure are transmitted to the Argo Data Centres.
By tracking the float positions each time they surface, they can also be used to track ocean currents.