Articles | Volume 14, issue 7
Geosci. Model Dev., 14, 4225–4240, 2021
Geosci. Model Dev., 14, 4225–4240, 2021

Development and technical paper 06 Jul 2021

Development and technical paper | 06 Jul 2021

SolveSAPHE-r2 (v2.0.1): revisiting and extending the Solver Suite for Alkalinity-PH Equations for usage with CO2, HCO3 or CO32− input data

Guy Munhoven

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Cited articles

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Byrne, R. H. and Yao, W.: Procedures for measurement of carbonate ion concentrations in seawater by direct spectrophotometric observations of Pb(II) complexation, Mar. Chem., 112, 128–135,, 2008. a
Deffeyes, K. S.: Carbonate Equilibria : A Graphic and Algebraic Approach, Limnol. Oceanogr., 10, 412–426,, 1965. a, b
Dickson, A. G., Sabine, C. L., and Christian, J. R. (Eds.): Guide to Best Practices for Ocean CO2 Measurements, vol. 3, in: PICES Special Publication, Carbon Dioxide Information and Analysis Center, Oak Ridge (TN), available at: (last access: 24 June 2021), 2007. a, b, c, d
Epitalon, J.-M., Gattuso, J.-P., and Munhoven, G.: SolveSAPHE: Solver Suite for Alkalinity-PH Equations, available at:, last access: 24 June 2021. a
Short summary
SolveSAPHE (Munhoven, 2013) was the first package to calculate pH reliably from any physically sensible pair of total alkalinity (AlkT) and dissolved inorganic carbon (CT) data and to do so in an autonomous and efficient way. Here, we extend it to use CO2, HCO3 or CO3 instead of CT. For each one of these pairs, the new SolveSAPHE calculates all of the possible pH values (0, 1, or 2), again without any prior knowledge of the solutions.