A broad-scale global array of temperature/salinity profiling floats, known as Argo, is planned as a major component of the ocean observing system, with deployment scheduled to begin in 2000. Conceptually, Argo builds on the existing upper-ocean thermal networks, extending ... their spatial and temporal coverage, depth range and accuracy, and enhancing them through addition of salinity and velocity measurements. The name Argo is chosen to emphasize the strong complementary relationship of the global float array with the Jason altimeter mission. For the first time, the physical state of the upper ocean will be systematically measured and assimilated in near real-time.
Objectives of Argo fall into several categories. Argo will provide a quantitative description of the evolving state of the upper ocean and the patterns of ocean climate variability, including heat and freshwater storage and transport. The data will enhance the value of the Jason altimeter through measurement of subsurface vertical structure (T(z), S(z)) and reference velocity, with sufficient coverage and resolution for interpretation of altimetric sea surface height variability. Argo data will be used for initialization of ocean and coupled forecast models, data assimilation and dynamical model testing. A primary focus of Argo is seasonal to decadal climate variability and predictability, but a wide range of applications for high-quality global ocean analyses is anticipated.
The initial design of the Argo network is based on experience from the present observing system, on newly gained knowledge of variability from the TOPEX/Poseidon altimeter, and on estimated requirements for climate and high-resolution ocean models. Argo will provide 100,000 T/S profiles and reference velocity measurements per year from about 3000 floats distributed over the global oceans at 3-degree spacing. Floats will cycle to 2000 m depth every 10 days, with a 4-5 year lifetime for individual instruments. All Argo data will be publicly available in near real-time via the GTS, and in scientifically quality-controlled form with a few months delay. Global coverage should be achieved during the Global Ocean Data Assimilation Experiment, which together with CLIVAR and GCOS/GOOS, provide the major scientific and operational impetus for Argo. The design emphasizes the need to integrate Argo within the overall framework of the global ocean observing system.
International planning for Argo, including sampling and technical issues, is coordinated by the Argo Science Team. Nations presently having Argo plans that include float procurement or production include Australia, Canada, France, Japan, U.K., and U.S.A., plus a European Union proposal. Combined deployments from these nations are expected to exceed 700 floats per year by 2002. Broad participation in Argo by many nations is anticipated and encouraged either through float procurement, logistical support for float deployment, or through analysis and assimilation of Argo data.
The Argo data (in NetCDF format) are freely available from two Argo Global Data Assembly Centres (GDAC): the Coriolis and US-GODAE GDAC servers. The Coriolis GDAC is updated daily in real-time data from Data Assembly Centers (DAC): US AOML, Canadian MEDS, Japanese JMA, EU Coriolis. The US- GODAE GDAC is currently operational, serving daily data (updated every hour) from the following national DACs: Australian (CSIRO), Canadian (MEDS), Indian (INCOIS), Korean ( KMA), Japanese (JMA), UK (BODC), and US (AOML).
ARGO Information Center provide data access through IFREMER/CORIOLIS and US- GODAE GDAC (HTTP, FTP, Live Access Server (LAS)), and information about deployment notification, project status, national programs, and tools ("interactive map" and "find floats").
This data set is part of the Global Ocean Data Assimilation Experiment (GODAE) data sets. The data along with information about the data can be accessed through the USGODAE GDAC (HTTP, FTP, Live Access Server and OPeNDAP/DODS server). To select profile, trajectory, or technical data by date, region, DAC, or float ID, use the USGODAE Argo GDAC Data Browser (http://www.usgodae.org/)