This is a Python re-write of the CSIRO seawater toolbox (SEAWATER-3.3) for calculating the properties of sea water. The package uses the formulas from Unesco’s joint panel on oceanographic tables and standards, UNESCO 1981 and UNESCO 1983 (EOS-80).

The EOS-80 library is considered now obsolete; it is provided here for compatibility with old scripts, and to allow a smooth transition to the new TEOS-10.


The Python version default output unit for sw.dist is ‘km’ instead of ‘nm’.

Here we assume pressure as the first dimension, i.e. M pressure by N positions (See the table below). The MatlabTM version does some guessing at this that we simply ignore to avoid confusions.

10 34.5487 28.7856
50 34.7275 28.4329
125 34.8605 22.8103
250 34.6810 10.2600
600 34.5680 6.8863
1000 34.5600 4.4036

The current version was tested against the MatlabTM seawater v3.3 reproducing all functions and results from that release.

Indices and tables