marelac (version 2.0)

sw_dens: Density of Sea Water

Description

Density of sea water in $kg m^{-3}$

Usage

sw_dens(S = 35, t = 25, p = max(0, P-1.013253), P = 1.013253,
  method=c("Gibbs","UNESCO","Chen"))

Arguments

S

Salinity, when method = "UNESCO": practical salinity (-) else absolute salinity (g/kg),

t

Temperature, $^\circ$C,

p

gauge or applied pressure, pressure referenced against the local atmospheric pressure, bar

P

true pressure, bar

method

When "UNESCO", uses the UNESCO (1983) polynomial, when "Gibbs", based on the Gibbs functions as in Feistel, 2008 "Chen" for the limnological range (i.e. fresh water systems).

Value

• Density of water in $kg m^{-3}$.

Details

To avoid confusion between the arguments (S, t, p) it is advisable to use named arguments in general (e.g. rho(t = 4). The UNESCO formula is imported from package seacarb.

References

Chen Ch.-T. and Millero FJ, 1986. Precise thermodynamic properties of natural waters covering only the limnological range. Limnol. Oceanogr. 31 No. 3, 657 - 662.

Fofonoff NP and Millard RC Jr, 1983. Algorithms for computation of fundamental properties of seawater. UNESCO technical papers in marine science, 44, 53 pp. http://unesdoc.unesco.org/images/0005/000598/059832EB.pdf

Feistel R, 2008. A Gibbs function for seawater thermodynamics for -6 to 80 dgC and salinity up to 120 g/kg. Deep-Sea Research I, 55, 1639-1671.

McDougall TJ, Feistel R, Millero FJ, Jackett DR, Wright DG, King BA, Marion GM, Chen C-T A and Spitzer P, 2009. Calculation of the Thermophysical Properties of Seawater, Global Ship-based Repeat Hydrography Manual, IOCCP Report No. 14, ICPO Publication Series no. 134.

See Also

rho in package seacarb.

sw_adtgrad, sw_alpha, sw_beta, sw_comp, sw_conserv, sw_cp, sw_depth, sw_enthalpy, sw_entropy, sw_gibbs, sw_kappa, sw_kappa_t, sw_sfac, sw_svel, sw_tfreeze, sw_tpot

convert_PStoAS, to convert from practical salinity to absolute salinity

convert_AStoPS, to convert from absolute salinity to practical salinity

Examples

# table 22 Feistel 2008
sw_dens(0,0,0)                #0.999843086e3
sw_dens(0,79.85,0)            #0.97188383e3   - deviates
sw_dens(0,0,998.98675)        #0.104527796e4

# table 21 Feistel 2008
sw_dens(35.16504,0,0)         #0.10281072e4
sw_dens(100,79.85,0)          #0.102985888e4
sw_dens(35.16504,0,998.98675) #0.10709264e4

sw_dens(35.7,25.5,102.3)      #1027.95249315662

S <- 0:40
plot(S, sw_dens(S = S, t = 4, method="UNESCO"))

lines(S, sw_dens(S = S, t = 4, method="Gibbs"),col="red")

lines(S, sw_dens(S = S, t = 4, method="Chen"),col="blue")