Argo Profiling Float Array

node · earth · Global ocean

A global fleet of autonomous floats that drift at about a kilometre depth, rise every ten days measuring temperature and salinity on the way up, transmit by satellite and sink again. Deployments began in 1999; the original design of 3,000 floats covering the open ocean between 60°S and 60°N on a three-degree grid was reached in November 2007, and the array now numbers over four thousand. The OneArgo design extends it to 4,700 floats including about a thousand carrying biogeochemical sensors. Argo is what turned ocean density — and therefore the density-driven circulation — from something known along a handful of ship tracks into something measured everywhere, all the time, and it is the reason the pre-2000 and post-2000 halves of the observational record are not comparable.