What Is Deep Argo?
The scientific community agrees that a systematic sampling of the full ocean depth is needed to close the planetary budgets of heat and freshwater, and the global sea level budget. The strength and variability of the large-scale ocean circulations that extend from the sea surface to the ocean bottom play significant roles in the uptakes and transports of heat and freshwater, and melting of sea ice. Since the implementation of the Argo program, profiling floats were limited to the top half of the sea (0-2000 m) and the accuracy of sensors was similarly limited to upper ocean levels of temperature and salinity variability. A new generation of autonomous floats called Deep Argo will sample the full ocean volume. Deep Argo float models include the Deep SOLO and Deep APEX capable of reaching 6000 m, and the Deep ARVOR and Deep NINJA designed to sample to 4000 m. Regional Deep Argo arrays in the Southwest Pacific Basin, South Australian Basin, Australian Antarctic Basin, and North Atlantic Ocean are leading the way forward to implement a standing Deep Argo array of 1228 floats. An exciting transition to systematic full-depth global ocean observations is happening.
One of the challenges facing Deep Argo is that the CTD sensor used on standard Argo floats was not designed to go below 2000 m depth. Therefore, SeaBird has
been working to develop a new CTD sensor that will be accurate down to 6000 m. This new CTD, named the SBE-61, has not yet achieved
its aspirational goals of (± .001C, ±.002 psu, and ± 3 dbar) but is progressing relative to those goals.
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Links to related papers
Zilberman, N, Roemmich D., 2017. The Argo Program samples the deep ocean. US CLIVAR Variations, 2(15):29-33
Jayne, S. R., D. Roemmich, N. V. Zilberman, S. C. Riser, K. S. Johnson, G. C. Johnson, and S. R. Piotrowicz, 2017: The Argo Program: Present and Future. Oceanography, 30, 18-28, http://dx.doi.org/10.5670/oceanog.2017.213
Zilberman, N. V., 2017: Deep Argo: Sampling the Total Ocean Volume in State of the Climate in 2016. Bull. Am. Meteorol. Soc., 98, S73-S74, https://doi.org/10.1175/2017BAMSStateoftheClimate.1
Le Reste, S., V. Dutreuil, X. André, V. Thierry, C. Renaut, P.-Y. L. Traon, and G. Maze, 2016: "Deep-Arvor": A New Profiling Float to Extend the Argo Observations Down to 4000-m Depth. Journal of Atmospheric and Oceanic Technology, 33, 1039-1055, http://dx.doi.org/10.1175/JTECH-D-15-0214.1
Johnson, G. C., J. M. Lyman, and S. G. Purkey, 2015: Informing Deep Argo Array Design Using Argo and Full-Depth Hydrographic Section Data. Journal of Atmospheric and Oceanic Technology, 32, 2187-2198, http://dx.doi.org/10.1175/JTECH-D-15-0139.1
Kobayashi, T., 2013: Deep NINJA collects profiles down to 4,000 meters. Sea Technology, 54, 41-44, https://www.sea-technology.com/features/2013/0213/deep_ninja.php
Kobayashi, T., 2013: A realization of a profiling float for deep ocean observation. Engineering Materials, 61, 67-70,
Kobayashi, T. and M. Tachikawa, 2013: An introduction of a domestic deep float, DEEP NINJA, and its deep/bottom layer observations in the Southern Ocean. JOS News Letter, 3,
Task team leads
The Deep Argo Task Team is comprised of:
Gregory C. Johnson
Photos above courtesy of LEARNZ
Photo above courtesy of Scripps Institution of Oceanography
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Teledyne Webb Research
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