Non-operational APEX autonomous drifting profiler, by Teledyne Webb Research, Massachusetts, United States, 2010. The Non-operational APEX autonomous drifting profiler was used to measure upper ocean temperature and salinity as part of the global Argo project.

Thousands of these robotic floats continually patrol Earth's upper ocean. The international Argo project was set up to measure how much heat is being absorbed by our oceans, and how the oceans move. Until the project began in 2000, scientific data about the ocean was sparse, mostly limited to measurements made by ships.

Argo floats are helping scientists to understand our complex planet, and the role oceans play in global climate change.