Precise representation of the P-V-T properties of water and seawater determined from sound speeds

Abstract

The compressibilities of water and seawater solutions have been determined from the sound speed measurements of Wilson [1959, 1960] by an iterative method. The compressibilities have been fit to (±0.02 × 10−6 bar−1 for pure water and ±0.01 × 10−6 bar−1 for seawater) an extended bulk modulus equation, (V0−VP)/P = D/(B + A1P + A2P2), where V0 and VP are the specific volumes at applied pressures of zero and P, D is Vw0 for pure water, and B, A1, and A2 are temperature and salinity dependent constants. The compressibilities of seawater derived from the sound data agree with Li's [1967] results at only 1 atm and agree with Crease's [1962] results at only low pressures. Since the maximum error in the compressibilities derived from sound speed data is within ±0.02 × 10−6 bar−1, our P-V-T results based on sound speed data are more reliable than any direct measurements made to date.