gsw (version 1.0-5)

gsw_SP_from_SA: Convert from Absolute Salinity to Practical Salinity

Description

Calculate Practical Salinity from Absolute Salinity, pressure, longitude, and latitude.

Usage

gsw_SP_from_SA(SA, p, longitude, latitude)

Arguments

SA

Absolute Salinity [ g/kg ]

p

sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar

longitude

longitude in decimal degrees, positive to the east of Greenwich. (This is called long in the TEOS-10 Matlab code.)

latitude

latitude in decimal degrees, positive to the north of the equator. (This is called lat in the TEOS-10 Matlab code.)

Value

Practical Salinity (PSS-78) [ unitless ]

Details

If SP is a matrix and if its dimensions correspond to the lengths of longitude and latitude, then the latter are converted to analogous matrices with expand.grid.

Note: unlike the corresponding Matlab function, this does not return a flag indicating whether the location is in the ocean.

The present R function works with a wrapper to a C function contained within the GSW-C system (Version 3.05-4 dated 2017-08-07, available at https://github.com/TEOS-10/GSW-C, as git commit '5b4d959e54031f9e972f3e863f63e67fa4f5bfec'), which stems from the GSW-Fortran system (https://github.com/TEOS-10/GSW-Fortran) which in turn stems from the GSW-Matlab system (https://github.com/TEOS-10/GSW-Matlab). Consult http://www.teos-10.org to learn more about these software systems, their authorships, and the science behind it all.

References

http://www.teos-10.org/pubs/gsw/html/gsw_SP_from_SA.html

See Also

Other things related to salinity: gsw_C_from_SP, gsw_SA_from_SP_Baltic, gsw_SA_from_SP, gsw_SA_from_Sstar, gsw_SP_from_C, gsw_SP_from_SK, gsw_SP_from_SR, gsw_SP_from_Sstar, gsw_SR_from_SP, gsw_Sstar_from_SA, gsw_Sstar_from_SP, gsw_deltaSA_from_SP

Examples

# NOT RUN {
SA <-   c(34.7118, 34.8915, 35.0256, 34.8472, 34.7366, 34.7324)
p <-    c(     10,      50,     125,     250,     600,    1000)
lat <-  c(      4,       4,       4,       4,       4,       4)
long <- c(    188,     188,     188,     188,     188,     188)
SP <- gsw_SP_from_SA(SA,p,long,lat)
expect_equal(SP, c(34.548721553448317, 34.727477488096639, 34.860554877708005,
                   34.680971112271791, 34.567971663653388, 34.560036751118204))
# }