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Supplementary Release on a Computationally Efficient Thermodynamic Formulation for Liquid Water for Oceanographic Use
September 2009

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This formulation is recommended for the calculation of thermodynamic properties of ordinary water in its liquid phase as the pure-water part of seawater calculations for oceanographic use where a simplified formulation is preferred.
The formulation is for the Gibbs energy as a function of temperature and pressure; appropriate combinations of derivatives can produce any thermodynamic property desired (density or specific volume, sound speed, heat capacity, enthalpy, entropy, etc.).
The formulation is valid and consistent with the IAPWS-95 formulation in entire region of ambient ocean water, up to 313.15 K and 100 MPa, including the metastable liquid phase found between the freezing temperatures of pure water and seawater.
The development of the formulation and comparisons to available data are described in detail in a scientific article.

Software Implementation
The IAPWS Subcommittee on Seawater, in cooperation with the SCOR/IAPSO Working Group 127, developed the "Thermodynamic Equation of Seawater 2010" (TEOS-10) which was endorsed as an international standard for oceanography by UNESCO-IOC in 2009 and by IUGG in 2011. The open-source code of TEOS-10 includes software implementations of this IAPWS formulation. Note that IAPWS is not responsible for the content of these external pages.

Revision History

This Supplementary Release is the product of the Working Group "Thermophysical Properties of Water and Steam" (TPWS) and the Subcommittee on Seawater (SCSW) of the International Association for the Properties of Water and Steam (IAPWS).

This page updated May 29, 2018

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