oce (version 0.9-3)

teos: Interface to TEOS-10 library

Description

Interface to TEOS-10 library

Usage

teos(name, a1, a2, a3, a4, lib=getOption("libteos"))

Arguments

name

the name of a TEOS-10 function. Note that the function names in the TEOS-10 documentation are in mixed case, but those in the actual TEOS-10 library are lower case. Thus, for example, the function to computer absolute salinity

a1

the first argument to the TEOS-10 function

a2

the second argument to the TEOS-10 function

a3

the third argument to the TEOS-10 function

a4

the fourth argument to the TEOS-10 function

lib

the name of the shared library that provides TEOS-10.

Value

• Whatever the TEOS-10 function returns, with dimensions matching those of a1. TEOS-10 functions use the value 9e15 to indicate invalid conditions (e.g. latitude exceeding 90 degrees), and these are converted by teos() to NA.

Details

#ifdef unix For teos to work, the user must download the C version of TEOS-10 from the website listed in the references, then type make install at the command line, and finally copy the resultant libgswteos-10.so file to the directory /usr/local/lib. For example, the steps listed below were used on the author's (OSX-based) machine. curl -OL http://www.teos-10.org/software/gsw_c_v3_0.zip unzip gsw_c_v3_0.zip cd gsw-3.0 make library sudo mv libgswteos-10.so /usr/local/lib If the library is installed elsewhere ("/opt/lib/libgswteos-10.so", to take an example), it will be necessary to note that fact, by performing two actions: option(libteos="/opt/lib/libgswteos10.so") .C("set_libteos", "/opt/lib/libgswteos10.so") #endif #ifdef windows For teos to work, the user must download the C source code for the TEOS-10 library and build it into a Windows DLL file. (At some time, perhaps the TEOS-10 team will supply DLL files, which would simplify matters for users.) Once that is done, it will be necessary to indicate to the the name and path of the library, e.g. (filling in NAME appropriately): option(libteos="NAME") .C("set_libteos", "NAME") #endif

References

[1] McDougall, T.J. and P.M. Barker, 2011: Getting started with TEOS-10 and the Gibbs Seawater (GSW) Oceanographic Toolbox, 28pp., SCOR/IAPSO WG127, ISBN 978-0-646-55621-5.

[2] The TEOS-10 library is provided at www.teos-10.org. [3] A programming interface to the matlab version of the TEOS library is provided at http://www.teos-10.org/pubs/gsw/html/gsw_contents.html.

See Also

swAbsoluteSalinity may be used to compute absolute salinity, and swConservativeTemperature may be used to compute conservative temperature. These values are used by plotTS if the eos argument is set to "teos".

Examples

## do not run this in checks, because it will fail unless TEOS-10 is installed
library(oce)
data(ctd)
sp <- ctd[["salinity"]]
temperature <- ctd[["temperature"]]
n <- length(sp)
p <- ctd[["pressure"]]
lat <- rep(ctd[["latitude"]], n)
lon <- rep(ctd[["longitude"]], n)
sa <- teos("gsw_sa_from_sp", sp, p, lon, lat)
par(mfrow=c(1,2))
plot(ctd, which="salinity")
lines(sa, p, col='red')
plot(ctd, which="density")
rhopot <- teos("gsw_pot_rho_t_exact", sa, temperature, p, rep(0,length(p)))
lines(rhopot - 1000, p, col='red')


## The following demonstrations are from test values from the TEOS-10 supplied
## program "gsw_check_functions.c".  (These, with more digits, are part of the
## test sequence that is run when Oce is built; see the tests/eos.R in the source
## code.)

# Absolute salinity is sa=35.671 g/kg, for practical salinity 35.5 PSU, pressure
# 300 dbar, long 300 degE, and lat 16 degN.
teos("gsw_sa_from_sp", 35.5, 300, 260, 16)

# Conservative temperature is ct=14.930, for abs sal=35.7 g/kg, in-situ temp 15
# degC, and press 300 dbar.
teos("gsw_ct_from_t", 35.7, 15, 300)

# Density is 1026.456 kg/m^3 for sa=35.7 g/kg, ct = 20 degC and p=300
teos("gsw_rho", 35.7, 20, 300)