Precise equation of state of seawater for oceanic ranges of salinity, temperature and pressure

Abstract

Abstract A 24-parameter equation of state for sea water was established for use in the open ocean (30 to 40‰ S , −2 to 38°C and up to 1000 bars). The equation of state is in the form: V P = V 0 − V 0 P/K 0 + AP + BP 2 ), where V P and V 0 are the specific volumes of seawater at applied pressures P and 0 (atmospheric pressure), respectively. V 0 , K 0 , A and B are all salinity- and temperature-dependent parameters. The short form equation of state is in excellent agreement (±2 × 10 −6 cm 3 g −1 in specific volume, ±1 × 10 −6 deg −1 in thermal expansibility and ±0.02 × 10 −6 bar −1 in isothermal compressibility) with the full, 48-parameter, equation of state for seawater (C. T. Chen and F. J. Millero , The specific volume of seawater at high pressures, Deep-Sea Research , 23 ,595–612,1976a) and is recommended for usage with calculations concerned with oceanic ranges of salinity, temperature, and pressure.