The situation is likely to change with the introduction of the Argo float programme. Argo floats are drifting platforms for the measurement of temperature and salinity as functions of depth over periods of years (Roemmich et al., 2004). They can be programmed individually for specific tasks; but a typical Argo float follows one of two operational modes. In the simple mode, the float drifts at a certain depth, often 2000m, rises to the surface every 10 days to take a temperature and salinity profile from that depth, stays at the surface for up to 12h to transmit the data via satellite, and returns to its deep drifting depth. In the park and profile mode, the float is parked at a certain depth (the Argo operations centre recommends 1000 m), descends to 2000m every 10 days to start the temperature and salinity profile, comes to the surface, transmits its data and returns to its parking depth. In the beginning of 2006, 46% of floats profile to around 2000m and 66% profile to depths greater than 1500m.