Argo (oceanography)

Argo is an international oceanographic observation system of the oceans, which to a fleet of more than 3600 robotic drifting buoys ( probes) various series for data recovery supports (as of February 2014).

The probes measure the salinity and sea temperature at depths of up to two kilometers and transmit them via satellite. Of position information and data about ocean currents are obtained. Some ranges detect further data, for example the oxygen content of the water. The collected data are freely available on the Internet.

The Argo program is a joint project of research institutions from 26 countries. The U.S. finance about half of the project, followed by Japan, Germany, France, Australia, South Korea and the UK.

Operation

The buoys have a ten-day measurement cycle. Here, a buoy drives around for nine days at a depth of 1000 m. On the tenth day it decreases to 2000 m, to then rise to the surface. The during the ascent determined, plotted versus water depth measurement data are transmitted by the satellite-based communication systems, Argos, with newer series also iridium, and the cycle begins anew.

The Argo program supplemented with its underwater oceanographic satellite measurements Jason, the data on the topography, ie collects the surface of the oceans.

The optimal lifetime of an Argo probe is about five years, with most battery life is the limiting factor. The buoys can not be recovered at end of life. Then you either sink to the seabed or are washed ashore somewhere. To maintain the Argo network, for the first time reached its target of 3,000 buoys end of 2007, so about 750 each year new buoy must be applied.

The regulation of the lift of the probes is done by the hydraulic expansion of a plastic bubble.

The data collected are free and accessible in real time on the internet. Access is via OPeNDAP.