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dc.contributor.authorGebbie, Geoffrey A.
dc.contributor.authorHuybers, Peter
dc.date.accessioned2012-03-26T17:49:27Z
dc.date.available2014-10-22T08:57:25Z
dc.date.issued2012-02
dc.identifier.citationJournal of Physical Oceanography 42 (2012): 291–305en_US
dc.identifier.urihttp://hdl.handle.net/1912/5098
dc.descriptionAuthor Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 291–305, doi:10.1175/JPO-D-11-043.1.en_US
dc.description.abstractA number of previous observational studies have found that the waters of the deep Pacific Ocean have an age, or elapsed time since contact with the surface, of 700–1000 yr. Numerical models suggest ages twice as old. Here, the authors present an inverse framework to determine the mean age and its upper and lower bounds given Global Ocean Data Analysis Project (GLODAP) radiocarbon observations, and they show that the potential range of ages increases with the number of constituents or sources that are included in the analysis. The inversion requires decomposing the World Ocean into source waters, which is obtained here using the total matrix intercomparison (TMI) method at up to 2° × 2° horizontal resolution with 11 113 surface sources. The authors find that the North Pacific at 2500-m depth can be no younger than 1100 yr old, which is older than some previous observational estimates. Accounting for the broadness of surface regions where waters originate leads to a reservoir-age correction of almost 100 yr smaller than would be estimated with a two or three water-mass decomposition and explains some of the discrepancy with previous observational studies. A best estimate of mean age is also presented using the mixing history along circulation pathways. Subject to the caveats that inference of the mixing history would benefit from further observations and that radiocarbon cannot rule out the presence of extremely old waters from exotic sources, the deep North Pacific waters are 1200–1500 yr old, which is more in line with existing numerical model results.en_US
dc.description.sponsorshipGG is supported by the J. Lamar Worzel Assistant Scientist Fund and the Penzance Endowed Fund in Support of Assistant Scientists. PJH is supported by NSF Award 0960787.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Meteorological Societyen_US
dc.relation.urihttps://doi.org/10.1175/JPO-D-11-043.1
dc.subjectNorth Pacific Oceanen_US
dc.subjectMass fluxes/transporten_US
dc.subjectOcean circulationen_US
dc.subjectTracersen_US
dc.subjectOptimizationen_US
dc.subjectVariational analysisen_US
dc.titleThe mean age of ocean waters inferred from radiocarbon observations : sensitivity to surface sources and accounting for mixing historiesen_US
dc.typeArticleen_US
dc.description.embargo2012-08-01
dc.identifier.doi10.1175/JPO-D-11-043.1


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