# Gibbs Sea Water (GSW) version history

## Version 3.01 (14th November 2011)

Bug fix in gsw_SA_Sstar_from_SP (line 182).

## Version 3.0 (15th May 2011)

Consists of approximately 166 functions.

Major improvements

- 48 term density equation introduced (intended for use by observational, theoretical oceanographers and ocean modellers). The use of a single density equation will ensure a unified field.
- the Absolute Salinity Anomaly takes into account evaporation and dilution.
- freezing temperatures
- isobaric melting enthalpy and isobaric evaporation enthalpy

Main changes

- all functions which have in-situ temperature t as the input temperature now end in "_t_exact"
- all functions which have Conservative Temperature CT as the input temperature and which are directly evaluated using the Gibbs function now end in "_CT_exact" (in version 2 they ended in "_CT")
- all functions which have Conservative Temperature CT as the input temperature and were based on the 25 term density equation have been replaced with the 48 term density function.
  The "_CT25" ending has been dropped.
- the 25 term density equation has been removed.
- all functions which have Conservative Temperature CT as the input temperature but use the 48 term density function can be called either with "_CT" at the end of their function names or without this ending. This point is the biggest change as many of these function names in version 2 used in-situ temperature (t) as the input temperature and the relied on the Gibbs function.
- Geostrophic streamfunctions now allow the user to define a reference pressure, and the options for the interpolation style and interpolated bottle resolution has been removed.

Bug fixes

## Version 2 (18th October 2010)

Consists of approximately 100 functions

Introduced

- the new naming structure for conversion functions, gsw_X_from_Y
- Streamfunctions
- water column properties
- neutral and non-linear properties
- planet Earth properties
- derivatives of enthalpy, entropy, Conservative temperature and potential temperature
- 25 term density equation (intended for modellers)

Major changes

- Absolute Salinity Anomaly extended to cover all areas of the ocean

Bug fixes

## Version 1 (1st January 2009)

Consists of approximately 16 functions

Introduction of the Absolute Salinity Anomaly