Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 10, 547-557, 2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
24 Jun 2014
Consistency of the current global ocean observing systems from an Argo perspective
K. von Schuckmann1, J.-B. Sallée2, D. Chambers3, P.-Y. Le Traon4, C. Cabanes5, F. Gaillard6, S. Speich7, and M. Hamon8 1Mediterranean Institute of Oceanography (MIO), Université de Toulon, Aix-Marseille Université, CNRS, IRD, MIO UM 110, La Garde, France
2Sorbonne Universités (Univ Paris 6)-IRD-CNRS-MNHN, LOCEAN, Paris, France and British Antarctic Survey, Cambridge, UK
3College of Marine Science, University of South Florida, St. Petersburg, Florida, USA
4Mercator Ocean and Ifremer, Ramonville, St. Agne, France
5CNRS, DT/INSU, Plouzané, France
6Ifremer, Brest, France
7UBO, Brest, France
8Mercator Ocean, Ramonville, St. Anne, France
Abstract. Variations in the world's ocean heat storage and its associated volume changes are a key factor to gauge global warming and to assess the earth's energy and sea level budget. Estimating global ocean heat content (GOHC) and global steric sea level (GSSL) with temperature/salinity data from the Argo network reveals a positive change of 0.5 ± 0.1 W m−2 (applied to the surface area of the ocean) and 0.5 ± 0.1 mm year−1 during the years 2005 to 2012, averaged between 60° S and 60° N and the 10–1500 m depth layer. In this study, we present an intercomparison of three global ocean observing systems: the Argo network, satellite gravimetry from GRACE and satellite altimetry. Their consistency is investigated from an Argo perspective at global and regional scales during the period 2005–2010. Although we can close the recent global ocean sea level budget within uncertainties, sampling inconsistencies need to be corrected for an accurate global budget due to systematic biases in GOHC and GSSL in the Tropical Ocean. Our findings show that the area around the Tropical Asian Archipelago (TAA) is important to closing the global sea level budget on interannual to decadal timescales, pointing out that the steric estimate from Argo is biased low, as the current mapping methods are insufficient to recover the steric signal in the TAA region. Both the large regional variability and the uncertainties in the current observing system prevent us from extracting indirect information regarding deep-ocean changes. This emphasizes the importance of continuing sustained effort in measuring the deep ocean from ship platforms and by beginning a much needed automated deep-Argo network.

Citation: von Schuckmann, K., Sallée, J.-B., Chambers, D., Le Traon, P.-Y., Cabanes, C., Gaillard, F., Speich, S., and Hamon, M.: Consistency of the current global ocean observing systems from an Argo perspective, Ocean Sci., 10, 547-557,, 2014.
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