Thermohaline equation of state for pure water, seawater and brine

Abstract

A thermohaline equation of state (EOS), relating the density of water to its temperature and salinity, is proposed for shallow water hydro-environment applications, at normal atmospheric pressure (101.3 kPa). The seawater is of standard ocean ionic composition. The proposed EOS applies to fresh, brackish, saline, hypersaline and brine water environments, in cold, temperate and hot climates. The density of water is considered nonlinear with temperature, but linear with salinity. This assumption is adequate for practical applications–allowing the transformation of the EOS into a relevant density difference equation–for calculating density differences and buoyancy in models of thermal and thermohaline flows in inland, estuarine, coastal and ocean waters.