A typical Argo float mission is to profile from 2000 m depth to the sea surface every 10 days. On deployment, the float sinks to a depth of 1000 m and drifts with the ocean currents for 9 days. Then the float sinks deeper to its profile depth (usually 2000 m) before starting to ascend through the water column measuring temperature, salinity and pressure as it rises. When the float reaches the surface it transmits location and profile data via satellite to land-based Argo data centres. After transmission the float sinks again and repeats the cycle.