# Gibbs Sea Water (GSW) version history

## Version 3.05 (22th May, 2015)

Added

- 75-term specific volume equation replaces the 48 term rational function.
  It is intended for use by observational, theoretical oceanographers
  and ocean modellers, both Boussinesq and non-Boussinesq.
  The use of a single specific volume equation will ensure a unified field.
- Reininger & Ross (1968) interpolation to dynamic height
- more gibbs derivatives (second and third derviatives)
- more polynomial versions of the functions in
  seawater and ice properties at freezing temperatures,
  thermodynamic interaction between ice and seawater
  thermodynamic interaction between sea ice and seawater
  and thermodynamic properties of ice Ih
spiciness
The following using 75 term polynomial and using the gibss function:
- first derivatives of specific volume
- second derivatives of specific volume
- first derivatives of specific volume with respect to enthalpy
- second derivatives of specific volume with respect to enthalpy
- specific volume anomaly
- second derivatives of density
- first derivatives of density with respect to enthalpy
- second derivatives of density with respect to enthalpy
- first derivatives of enthalpy
- second derivatives of enthalpy
- first derivatives of internal energy
- second derivatives of internal energy
- gsw_travel_time
- gsw_frazil_properties
- gsw_frazil_properties_potential
- gsw_frazil_properties_potential_poly

Renamed gsw_brineSA_CT to gsw_SA_freezing_from_CT

Renamed gsw_brineSA_CT_poly to gsw_SA_freezing_from_CT_poly

Renamed gsw_brineSA_t to gsw_SA_freezing_from_t

Renamed gsw_brineSA_t_poly to gsw_SA_freezing_from_t_poly

Renamed gsw_frazil_ratios to gsw_frazil_ratios_adiabatic

Renamed gsw_specvol_amon to gsw_specvol_amon_standard

Renamed gsw_specvol_amon_CT_exact to gsw_specvol_amon_standard_CT_exact

Renamed gsw_specvol_amon_t_exact to gsw_specvol_amon_standard_t_exact

## Version 3.04 (20th December, 2013)

Added

- seawater properties at the freezing temperature
- thermodynamic properties of ice Ih
- thermodynamic interaction between ice Ih and seawater
- thermodynamic interaction between sea ice and seawater
- dissolved gasses
- gsw_CT_from_enthalpy and gsw_CT_from_enthalpy_exact
- gsw_CT_first_derivatives_wrt_t_exact
- gsw_enthalpy_first_derivatives_wrt_t_exact
- gsw_t_deriv_chem_potential_water_t_exact

Renamed gsw_streric_height to gsw_geo_strf_steric_height

Renamed gsw_CT_freezing to gsw_CT_freezing_poly

Renamed gsw_t_freezing to gsw_t_freezing_poly

Renamed gsw_brineSA_CT to gsw_brineSA_CT_poly

Renamed gsw_brineSA_t to gsw_brineSA_t_poly

This is the final version where functions based on the 48-term expression for density that end in "_CT" are supported

## Version 3.03 (8th June, 2013)

Added

- isentropic compressibility (kappa) for the 48-term equation of state.
- gsw_rho_first derivatves and gsw_rho_first derivatves_CT_exact.
- gsw_alpha_on_beta and gsw_alpha_on_beta_CT_exact.
- gsw_t_from_pt0
- gsw_t_from_entropy
- gsw_adiabatic_lapse_rate_from_CT.
- gsw_deltaSA_from_rho_t_exact.

Remaned gsw_entropy_t_exact to gsw_entropy_from_t, and added ths inverse function (gsw_t_from_entropy)

Renamed gsw_adiabatic_lapse_rate_t_exact to gsw_adiabatic_lapse_rate_from_t

## Version 3.02 (20th November, 2012)

Improved computation efficiency.

Minor bug fixes.

## 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