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Fifteen years of ocean observations with the global Argo array

Abstract

More than 90% of the heat energy accumulation in the climate system between 1971 and the present has been in the ocean. Thus, the ocean plays a crucial role in determining the climate of the planet. Observing the oceans is problematic even under the most favourable of conditions. Historically, shipboard ocean sampling has left vast expanses, particularly in the Southern Ocean, unobserved for long periods of time. Within the past 15 years, with the advent of the global Argo array of profiling floats, it has become possible to sample the upper 2,000 m of the ocean globally and uniformly in space and time. The primary goal of Argo is to create a systematic global network of profiling floats that can be integrated with other elements of the Global Ocean Observing System. The network provides freely available temperature and salinity data from the upper 2,000 m of the ocean with global coverage. The data are available within 24 hours of collection for use in a broad range of applications that focus on examining climate-relevant variability on seasonal to decadal timescales, multidecadal climate change, improved initialization of coupled ocean–atmosphere climate models and constraining ocean analysis and forecasting systems.

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Figure 1: The typical cycle of an Argo float.
Figure 2: The sampling density of profiles reported by Argo floats.
Figure 3: Mean temperature over the period 2004–2010 in the global ocean.
Figure 4: Convection in the Labrador Sea.
Figure 5: Argo estimates of global heat content.

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Acknowledgements

Argo data were collected and made freely available by the International Argo Programme and the national programmes that contribute to it. The Argo Programme is part of the Global Ocean Observing System. Thanks to Igor Yashayaev for constructing Fig. 4 as his contribution to the Atlantic Zone Off-Shelf Monitoring Program (led by the Department of Fisheries and Oceans, Canada) and to the International Argo Programme.

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The paper was written by S.C.R. (60%) and H.J.F. (40%), with editorial comments and suggestions provided by the remaining co-authors who have all served as members of the Argo Steering Team and so have contributed significantly to the Argo programme.

Corresponding author

Correspondence to Howard J. Freeland.

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The authors declare no competing financial interests.

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Riser, S., Freeland, H., Roemmich, D. et al. Fifteen years of ocean observations with the global Argo array. Nature Clim Change 6, 145–153 (2016). https://doi.org/10.1038/nclimate2872

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