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dc.contributor.authorOrr, J.C.
dc.contributor.authorEpitalon, J.-M.
dc.contributor.authorGattuso, J.-P.
dc.identifier.citationOrr, J.C.; Epitalon, J-M. and Gattuo, J-P. (2015) Comparison of ten packages that compute ocean carbonate chemistry. Biogeosciences, 12, pp.1483-1510. DOI:10.5194/bg-12-1483-2015en_US
dc.description.abstractMarine scientists often use two measured or modeled carbonate system variables to compute others. These carbonate chemistry calculations, based on well-known thermodynamic equilibria, are now available in a dozen pub- lic packages. Ten of those were compared using common input data and the set of equilibrium constants recommended for best practices. Current versions of all 10 pack- ages agree within 0.2 μatm pCO2, 0.0002 units for pH,and 0.1 μmol kg−1 for CO2−3 in terms of surface zonal-mean values. That represents more than a 10-fold improvement relative to outdated versions of the same packages. Differences between packages grow with depth for some computed variables but remain small. Discrepancies derive largely from differences in equilibrium constants. Analysis of the sensitivity of each computed variable to changes in each constant reveals the general dominance of K1 and K2 but also the comparable sensitivity to KB for the AT–CT input pair. Best-practice formulations for K1 and K2 are implemented consistently among packages. Yet with more recent formulations designed to cover a wider range of salinity, packages disagree by up to 8 μatm in pCO2, 0.006 units in pH, and 1 μmol kg−1 in CO2−3 under typical surface conditions. They use different proposed sets of coefficients for these formulations, all of which are inconsistent. Users would do well to use up-to-date versions of packages and the constants recommended for best practicesen_US
dc.rightsAttribution 3.0 IGO*
dc.subject.otherCarbonate chemistryen_US
dc.subject.otherEquilibrium constantsen_US
dc.titleComparison of ten packages that compute ocean carbonate chemistry.en_US
dc.typeJournal Contributionen_US
dc.subject.parameterDisciplineParameter Discipline::Chemical oceanography::Carbonate systemen_US
dc.subject.dmProcessesData Management Practices::Data analysisen_US
dc.description.bptypeBest Practiceen_US

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Attribution 3.0 IGO
Except where otherwise noted, this item's license is described as Attribution 3.0 IGO