## Contents

## USAGE:

SP = gsw_SP_from_R(R,t,p)

## DESCRIPTION:

Calculates Practical Salinity, SP, from the conductivity ratio, R,
primarily using the PSS-78 algorithm. Note that the PSS-78 algorithm
for Practical Salinity is only valid in the range 2 < SP < 42. If the
PSS-78 algorithm produces a Practical Salinity that is less than 2 then
the Practical Salinity is recalculated with a modified form of the
Hill et al. (1986) formula. The modification of the Hill et al. (1986)
expression are to ensure that it is exactly consistent with PSS-78
at SP = 2.

## INPUT:

R = Conductivity ratio [ unitless ]
t = in-situ temperature (ITS-90) [ deg C ]
p = sea pressure [ dbar ]
( ie. absolute pressure - 10.1325 dbar )

t & p may have dimensions 1x1 or Mx1 or 1xN or MxN, where R is MxN.

## OUTPUT:

SP = Practical Salinity on the PSS-78 scale [ unitless ]

## EXAMPLE:

R = [ 1.3145; 1.3123; 1.1807; 0.8886; 0.8169; 0.7687;]
t = [28.7856; 28.4329; 22.8103; 10.2600; 6.8863; 4.4036;]
p = [ 10; 50; 125; 250; 600; 1000;]

SP = gsw_SP_from_R(R,t,p)

SP =

34.547219254816596
34.727400381174370
34.859100827188712
34.679845200922003
34.567856165219020
34.561679175326645

## AUTHOR:

Trevor McDougall and Paul Barker [ help@teos-10.org ]

## VERSION NUMBER:

3.05 (16th February, 2015)

## REFERENCES:

Hill, K.D., T.M. Dauphinee and D.J. Woods, 1986: The extension of the
Practical Salinity Scale 1978 to low salinities. IEEE J. Oceanic Eng.,
OE-11, 1, 109 - 112.

IOC, SCOR and IAPSO, 2010: The international thermodynamic equation of
seawater - 2010: Calculation and use of thermodynamic properties.
Intergovernmental Oceanographic Commission, Manuals and Guides No. 56,
UNESCO (English), 196 pp. Available from the TEOS-10 web site.
See appendix E of this TEOS-10 Manual.

Unesco, 1983: Algorithms for computation of fundamental properties of
seawater. Unesco Technical Papers in Marine Science, 44, 53 pp.

The software is available from http://www.TEOS-10.org