Float Tracks: Argo (buoy depths animation)
"Argo is a global array of 3,000 free-drifting profiling floats that measures the temperature and salinity of the upper 2000 m of the ocean. This allows, for the first time, continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection." - from the Argo website. In Greek mythology, Jason sailed on the ship Argo to capture a golden fleece. In the world of oceanography, Jason is a satellite altimeter that allows scientists to measure the heights of the ocean surfaces. This worldwide buoy program was named Argo because the data from the Jason project and from this buoy project will be used together in computer models to help forecast ocean climate.
In order to measure temperature and salinity of the upper 2000m (over 6500ft) of the ocean, the Argo floats are designed to be neutrally buoyant at the "parking depth" which is typically 2000m. They drift along at this level for many days, recording data before an external bladder on the buoy causes it to slowly rise to the surface over a six-hour period. During the ascent, measurements are continuously taken. Once at the surface, satellites are used to determine the float's position and to receive the data transmitted by the instrument. After that has been completed, the bladder deflates and the float sinks back down to its parking depth. The whole cycle typically takes 10 days. This visualization shows the drifting movement across the oceans, but also their descent and ascent. The lighter floats are at the sea surface while the darker floats are below the sea surface. The dataset is referred to as "waterfall" because the data during the ascent of the float, when plotted, looks like a waterfall.
- Each dot is an Argo float
- Lighter dots are buoys on the sea surface and the darker ones are below the surface