ARGO (part of the integrated global observation strategy) 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.’

The buoys are pre-programmed and move to depth by increasing and decreasing the amount of water in the structure. This visualisation shows the locations of the ARGO buoy array over time. When the bouys are above water, the lines are brighter; when the buoys are under water, the lines are fainter.

The buoys can also be tracked using Google Earth at this link, and by clicking on the green floats the most recent data can be viewed. The information also includes the country of origin of the buoy.

Image courtesy of NASA/Goddard Space Flight Center Scientific Visualization Studio