Argo is an international program to deploy 3,000 profiling floats to collect observations of the temperature and salinity structure of the upper ocean--globally and in real-time. Subsurface observations from Argo--combined with surface temperature, topography, and winds observed by existing satellites--will enable advances both in research programs such as CLIVAR and in operational demonstrations such as GODAE.

Argo floats can be deployed by C-130 aircraft or ships of opportunity Air deployments include secure packaging and parachute Upon impact, the float is released to sink Video courtesy of Webb Research

Argo floats are programmed to sink to 2,000 meters They drift at depth for 10 days Then they rise to the surface measuring temperature and salinity Data and position are transmitted ashore via satellite Animation courtesy of Tim Silva, WHOI

All data are freely available in real-time and delayed mode. Floats have a 4-year design life. Courtesy of Jack Cook,WHOI

Indian Ocean Float Trajectories 1000-m depth 25-day steps Jan 95 - Dec 98 Courtesy of Breck Owens, WHOI & Russ Davis, SIO Argo floats are a derivative of ALACE floats developed by the World Ocean Circulation Experiment (WOCE) with NSF funding. ALACE floats estimate currents at a fixed depth. Over 1,000 have been deployed during the past decade. Here is a four-year record of trajectories of ALACE floats deployed in the Indian Ocean as part of WOCE.

Indian Ocean Float Trajectories 1000-m depth 25-day steps Jan 95 - Dec 98 Courtesy of Breck Owens, WHOI & Russ Davis, SIO

Labrador Sea Float Trajectories 600 & 1400 m 10-day steps Jan 97 - Dec 98 Courtesy of Breck Owens, WHOI & Russ Davis, SIO Here is a two-year record of trajectories of floats deployed in the Labrador Sea. All floats were equipped to take temperature profiles. These are PALACE, or ‘profiling’ ALACE, floats. Some took salinity profiles as well; and as such, they serve as prototypes for Argo. These floats were deployed with support from NSF for WOCE and ONR for the Convection ARI.

Labrador Sea Float Trajectories 600 & 1400 m 10-day steps Jan 97 - Dec 98 Courtesy of Breck Owens, WHOI & Russ Davis, SIO

Mixed Layer Depth Deepest Blue 1,000 m or more 10-day steps Jan 97 - Dec 98 Courtesy of Breck Owens, WHOI & Russ Davis, SIO Here is a two-year record of the mixed layer depth derived from Labrador Sea temperature profiles. The mixed layer is defined as the maximum depth at which the water is no colder than 1 degree C of the surface temperature. In winter, the ‘deep blue’ indicates deep vertical mixing extending to 1,000 meters or more. This corresponds to locations where surface water has been cooled sufficiently to sink and mix, forming ‘Labrador Sea Water’. In summer, the ‘red’ indicates a warm, shallow mixed layer of ~10 m depth.

Mixed Layer Depth Deepest Blue 1,000 m or more 10-day steps Jan 97 - Dec 98 Courtesy of Breck Owens, WHOI & Russ Davis, SIO

Argo Observing the ocean in real-time To improve our understanding of the ocean and its circulation To advance our capability to forecast the ocean and its influence on climate

The U.S. contribution to Argo is managed by the National Oceanographic Partnership Program, with funding from ONR and NOAA. Argo international activities are coordinated by the World Meteorological Organization and the Intergovernmental Oceanographic Commission through their joint Technical Commission for Oceanography and Marine Meteorology.