Skip to contents

Absolute Salinity Anomaly from Practical Salinity

Usage

gsw_deltaSA_from_SP(SP, p, longitude, latitude)

Arguments

SP

Practical Salinity (PSS-78) [ unitless ]. The valid range for most `gsw` functions is from 2 to 42.

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

deltaSA Absolute Salinity Anomaly [ g/kg ]

Implementation Note

This R function uses a wrapper to a C function contained within the GSW-C system as updated 2022-10-11 at https://github.com/TEOS-10/GSW-C with git commit `657216dd4f5ea079b5f0e021a4163e2d26893371`.

The C function uses data from the library/gsw_data_v3_0.mat file provided in the GSW-Matlab source code, version 3.06-11. Unfortunately, this version of the mat file is no longer displayed on the TEOS-10.org website. Therefore, in the interests of making GSW-R be self-contained, a copy was downloaded from http://www.teos-10.org/software/gsw_matlab_v3_06_11.zip on 2022-05-25, the .mat file was stored in the developer/create_data directory of https://github.com/TEOS-10/GSW-R, and then the dataset used in GSW-R was created based on that .mat file.

Please consult http://www.teos-10.org to learn more about the various TEOS-10 software systems.

Examples

SP =   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)
deltaSA = gsw_deltaSA_from_SP(SP,p,long,lat)
stopifnot(all.equal(deltaSA, c(0.000167203365230, 0.000268836122231, 0.000665803155705,
                               0.002706154619403, 0.005652977406832,  0.009444734661606)))