SolveSAPHE (Solver Suite for Alkalinity-PH Equations)

SolveSAPHE (Solver Suite for Alkalinity-PH Equations) provides a collection of Fortran 90 routines to solve the total alkalinity–pH equation, which relates total alkalinity and pH for a given set of total concentrations of the acid–base systems that contribute to total alkalinity in a given water sample.

This package was first published as a supplement to the discussion paper:

Guy Munhoven (2013) The mathematics of the total alkalinity-pH equation: pathway to robust and universal solution algorithms, Geosci. Model Dev. Discuss., 6, 2087–2136, 2013 (URL: https://www.geosci-model-dev-discuss.net/6/2087/2013 or doi:10.5194/gmdd-6-2087-2013)

The package provides six different solvers for the alkalinity-pH equation: two of the six solvers implement variants of a newly developed iterative algorithm, designed to assure convergence with any physically meaningful chemical composition; the four others are re-implementations of previously published algorithms. Furthermore, a collection of parametrizations for stoichiometric constants for seawater samples is included.