International one-atmosphere equation of state of seawater

Abstract

The density measurements by Millero, Gonzalez and Ward (1976, Journal of Marine Research,34, 61–93) and Poisson, Brunet and Brun-Cottan (1980, Deep-Sea Research, 27, 1013–1028), from 0 to 40°C and 0.5 to 43 salinity, have been used to determine a new 1-atm equation of state for seawater. The equation is of the form (t°C; S; ϱ kg m−3)ρ=ρ0+AS+BS32+CS, where A=8.24493×10−1−4.0899×10−3t+7.6438×10−5t2−8.2467×10−7t3+5.3875×10−9t4B=−5.72466×10−3+1.0227×10−4t−1.6546×10−6t2C=4.8314×10−4 and ϱ0 is the density of water (Bigg, 1967, British Journal of Applied Physics, 8, 521–537). ρ0=999.842594+6.793952×10−2t−9.095290×−3t2+1.001685×10−4t3−1.120083×10−6t4+6.536336×10−9t5. The standard error of the equation is 3.6 × 10−3 kg m−3. This equation will become the new 1-atm equation of state of seawater that has been suggested for use by the UNESCO (United Nations Educational, Scientific and Cultural Organization) joint panel on oceanographic tables and standards.