By Theresa Williams
Our final science mission was to deploy Argo floats in international waters along our route back to Chile. The plan is to have a float in every three-minute by three-minute square of latitude and longitude all over the world’s oceans. We lowered one off the back of the ship about every 26 hours as we came to the scheduled locations.
An Argo float is a battery-powered autonomous float that sinks to 1000 meters and drifts in the current for nine days. On the tenth day, it sinks to 2000 meters then begins measuring temperature and salinity as it rises to the surface over a six-hour period. It spends six to twelve hours at the surface as it transmits its data over satellite, then it sinks back down to 1000 meters again to repeat the process.
There are currently about 4000 of these drifting profiling floats deployed world-wide. They’ve been observing temperature, salinity and currents in Earth’s oceans since the early 2000s. Argo floats provide real-time data for climate and oceanographic research.