seawater 3.3

Seawater Libray for Python

Python Seawater

The CSIRO seawater toolbox ([SEAWATER-3.3](http://www.cmar.csiro.au/datacentre/ext_docs/seawater.htm)) 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.

gibbs vs. csiro

This table shows some function names in the gibbs library and the corresponding function names in the csiro library.

Variable	SeaWater & ESO‐80	Gibbs‐SeaWater (GSW) & TEOS‐10
Absolute Salinity	NA	gsw.SA_from_SP(SP,p,long,lat)
Conservative Temperature	NA	gsw.CT_from_t(SA,t,p)
density (i.e. in situ density)	sw.dens(SP,t,p)	gsw.rho_CT(SA,CT,p), or gsw.rho(SA,t,p), or gsw.rho_CT25(SA,CT,p)
potential density	sw.pden(SP,t,p,pr)	gsw.rho_CT(SA,CT,pr), or gsw.rho_CT25(SA,CT,pr)
potential temperature	sw.ptmp(SP,t,p,pr)	gsw.pt_from_t(SA,t,p,pr)
$sigma_0$, using $theta_o$ = sw.ptmp(SP,t,p,0)	sw.dens(SP, $theta_o$, 0) -1000 kg m $^{-3}$	gsw.sigma0_CT(SA,CT)
$sigma_2$, using $theta_2$ = sw.ptmp(SP,t,p,2000)	sw.dens(SP,$theta_2$, 2000) -1000 kg m $^{-3}$	gsw.sigma2_CT(SA,CT)
$sigma_4$, using $theta_4$ = sw.ptmp(SP,t,p,2000)	sw.dens(SP,$theta_4$, 4000) -1000 kg m $^{-3}$	gsw.sigma2_CT(SA,CT)
specific volume anomaly	sw.svan(SP,t,p)	gsw.specvol_anom_CT(SA,CT,p) or gsw.specvol_anom_CT25(SA,CT,p)
dynamic height anomaly	-sw.gpan(SP,t,p)	gsw.geo_strf_dyn_height(SA,CT,p,delta_p,interp_style)
geostrophic velocity	sw.gvel(ga,lat,long)	gsw.geostrophic_velocity(geo_str,long,lat,p)
N $^2$	sw.bfrq(SP,t,p,lat)	gsw.Nsquared_CT25(SA,CT,p,lat)
pressure from height (SW uses depth, not height)	sw.pres(-z,lat)	gsw.p_from_z(z,lat)
height from pressure (SW outputs depth, not height)	z = -sw.dpth(p,lat)	gsw.z_from_p(p,lat)
in situ temperature from pt	sw.temp(SP,pt,p,pr)	gsw.pt_from_t(SA,pt,pr,p)
sound speed	sw.svel(SP,t,p)	gsw.sound_speed(SA,t,p)
isobaric heat capacity	sw.cp(SP,t,p)	gsw.cp(SA,t,p)
adiabatic lapse rate*	sw.adtg(SP,t,p)	gsw.adiabatic_lapse_rate(SA,t,p)
SP from cndr, (PSS‐78)	sw.salt(cndr,t,p)	gsw.SP_from_cndr(cndr,t,p)
cndr from SP, (PSS‐78)	sw.cndr(SP,t,p)	gsw.cndr_from_SP(SP,t,p)
distance	sw.dist(lat,long,units)	gsw.distance(long,lat,p)
gravitational acceleration	sw.g(lat,z)	gsw.grav(lat,p)
Coriolis parameter	sw.f(lat)	gsw.f(lat)
testing of all functions	sw.test()	gsw.test()

* The sw and gsw functions output the adiabatic lapse rate in different units being K (dbar) $^{-1}$ and K Pa $^{-1}$ respectively.

More information:

http://pypi.python.org/pypi/seawater/

What’s new in this version of seawater

19 April 2006 release 3.2

Corrected sign of potential vorticity in bfrq.

24 November 2005 release 3.1

Added swvel to compute surface wave velocity.

12 December 2003 release 3.0

Converted code so that temperature is now ITS-90 throughout.

25 June 1999 release 2.0.2

Coding changes to enable functions to return the same shape vector as the input arguments. In previous releases, some functions returned column vectors for row vector input. Also some other tidying up.

22 April 1998 release 2.0.1

satAr New routine. Solubility of Ar in seawater satN2 New routine. Solubility of N2 in seawater satO2 New routine. Solubility of O2 in seawater test Updated to include tests for above

April 1998 release 1.2e

alpha Fixed bug where temp used in calculations regardless of the keyword.

15 November 1994 release 1.2d

bfrq Now also returns potential vorticity. Thanks to Greg Johnson

([e-mail])

gvel OMEGA=7.29e-5 changed to OMEGA=7.292e-5 to be consistent with f

IMPORTANT API CHANGE: The usage of alpha, beta and aonb routines has changed! All these routines expect (S,T,P) to be passed instead of (S,PTMP,P) as in previous releases of seawater. Fast execution can still be obtained by passing ptmp=True see help.

19 October 1994 release 1.2c

bfrq Fixed bug where LAT = [] was needed as argument when no latitude

values are being passed. Now pass PRESSURE instead of DEPTH -> more consistent though only a negligible change is answers.

12 October 1994 release 1.2b

First official release and announcement on the networks.