Density of standard seawater by vibrating tube densimeter: Analysis of the method and results

Abstract

Seawater density has a great importance in oceanography, since it drives the ocean currents that drift oxygen, heat, plankton and pollutants. If the density is measured with high accuracy, it can be also used for salinity determination. In this work, the density of standard seawater was measured at different absolute salinities from (10.044–38.178) g kg−1, in the temperature range of (278.15–313.15) K at atmospheric pressure. The measurements were carried out by means of a commercial vibrating tube densimeter, following the substitution method (alternating samples of seawater and water) and under conditions typical of the most oceanographic laboratories capabilities. Besides, an accurate analysis of the uncertainty of density was performed, obtaining a relative expanded uncertainty of 0.003% (k=2). Measurements were compared with the density values provided by the international reference equation of state: the Thermodynamic Equation of SeaWater-2010, TEOS-10.