# gsw_SP_from_R

    Practical Salinity from conductivity ratio,R

## Contents

- USAGE:
- DESCRIPTION:
- INPUT:
- OUTPUT:
- EXAMPLE:
- AUTHOR:
- VERSION NUMBER:
- REFERENCES:

## 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.

    Click for a more detailed description of calculating
    Practical Salinity from conductivity ratio.

## 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:

    3.01 (23rd May, 2011)

## 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