Annie P. S. Wong, Susan E. Wijffels, Stephen C. Riser, Sylvie Pouliquen, Shigeki Hosoda, Dean Roemmich, et al.

SYSTEMATIC REVIEW ARTICLE published in Frontiers in Marine Science, SEP 2020

In the past two decades, the Argo Program has collected, processed, and distributed over two million vertical profiles of temperature and salinity from the upper two kilometers of the global ocean. A similar number of subsurface velocity observations near 1,000 dbar have also been collected. This paper recounts the history of the global Argo Program, from its aspiration arising out of the World Ocean Circulation Experiment, to the development and implementation of its instrumentation and telecommunication systems, and the various technical problems encountered. We describe the Argo data system and its quality control procedures, and the gradual changes in the vertical resolution and spatial coverage of Argo data from 1999 to 2019. The accuracies of the float data have been assessed by comparison with high-quality shipboard measurements, and are concluded to be 0.002°C for temperature, 2.4 dbar for pressure, and 0.01 PSS-78 for salinity, after delayed-mode adjustments. Finally, the challenges faced by the vision of an expanding Argo Program beyond 2020 are discussed.

Fig. A schematic illustration of the standard Argo “park-and-profile” mission. The surface interval of ~20 min is applicable to floats that use Iridium satellite communication; floats that use ARGOS satellite communication require surface interval of several hours for data telemetry.
[Source: Woods Hole Oceanographic Institution].

https://doi.org/10.3389/fmars.2020.00700