R: Second Derivatives of Specific Volume

gsw_specvol_second_derivatives {gsw} | R Documentation

## Second Derivatives of Specific Volume

### Description

Second Derivatives of Specific Volume

### Usage

    gsw_specvol_second_derivatives(SA, CT, p)

### Arguments

`SA` | Absolute Salinity [ g/kg ]
`CT` | Conservative Temperature [ degC ]
`p` | sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar

### Details

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.

### Value

A list containing `specvol_SA_SA` [ (m^3/kg)/(g/kg)^2 ], the second derivative of specific volume with respect to Absolute Salinity, `specvol_SA_CT` [ (m^3/kg)/(g/kg)/degC ], the derivative of specific volume with respect to Absolute Salinity and Conservative Temperature, `specvol_CT_CT` [ (m^3/kg)/degC^2 ], the second derivative of specific volume with respect to Conservative Temperature, `specvol_SA_p` [ (m^3/kg)/(g/kg)/dbar ], the derivative of specific volume with respect to Absolute Salinity and pressure, and `specvol_CT_p` [ (m^3/kg)/K/dbar ], the derivative of specific volume with respect to Conservative Temperature and pressure.

### References

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

### Examples

    SA <- c(34.7118, 34.8915, 35.0256, 34.8472, 34.7366, 34.7324)
    CT <- c(28.7856, 28.4329, 22.8103, 10.2600,  6.8863,  4.4036)
    p <- c(      10,      50,     125,     250,     600,    1000)
    r <- gsw_specvol_second_derivatives(SA, CT, p)
    expect_equal(r$specvol_SA_SA/1e-8, c(0.080906777599140, 0.080915086639384, 0.084568844270812,
                                       0.096725108896007, 0.099111765836648, 0.100302277946072))
    expect_equal(r$specvol_SA_CT/1e-8, c(0.129965332117084, 0.130523053162130, 0.149555815430615,
                                       0.217023290441810, 0.233892039070486, 0.243659989480325))
    expect_equal(r$specvol_CT_CT/1e-7, c(0.071409582006642, 0.071582962051991, 0.077436153664104,
                                       0.095329736274850, 0.100105336953738, 0.103044572835472))
    expect_equal(r$specvol_SA_p/1e-14, c(0.141281359467752, 0.141507584673426, 0.147247234588907,
                                       0.164580347761218, 0.168069801298412, 0.169948275518754))
    expect_equal(r$specvol_CT_p/1e-14, c(0.085542828707964, 0.086723632576213, 0.112156562396990,
                                       0.188269893599500, 0.211615556759369, 0.228609575049911))

[Package gsw version 1.0-5 Index]