A Sea Water Equation of State Calculator
To use the calculator:
The equation of state of water is a complicated curve fit to very precise measurements. The relationship between the Practical Salinity Scale and older measures of salinity (typically measured in parts per thousand) is nearly, but not quite 1:1. In addition the conversion from absolute conductivity to salinity is discussed in some detail in Fofonoff. The interested reader is urged to read that article for a more complete discussion of these issues.
Although the actual equation of state is quite complex there is a simple rule of thumb to remember that can be quite helpful: density increases by roughly 1 part per 1000 when the temperature decreases by 5 deg C, the salinity increases by 1 psu or the pressure increases by 200 dbar (about 200 m depth).
Range of Validity:
The underlying equations are valid for temperatures from -2 to 35 deg C, pressures from 0 to 10,000 dbar, and practical salinity from 2 to 42.
© The Johns Hopkins University Applied Physics Laboratory
Update:Nov 26 17:17:54 2006