# sw_svel: Velocity of the Sound in Seawater In marelac: Tools for Aquatic Sciences

 sw_svel R Documentation

## Velocity of the Sound in Seawater

### Description

Computes the velocity of the sound in seawater, using the UNESCO 1983 polynomial or based on the Gibbs function.

Valid for salinity from 0 to 40, temperature from 0 to 40 dgC, pressure from 1 to 1000 bars.

### Usage

``````sw_svel(S = 35, t = 25, p = P-1.013253, P = 1.013253,
method = c("Gibbs", "UNESCO"))
``````

### 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

### Value

Sound velocity, in m / sec.

### Note

Sound velocity for S = 40, t = 40, p = 1000 is 1731.995 using UNESCO polynomial.

### Author(s)

Karline Soetaert <karline.soetaert@nioz.nl>

### References

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.

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

`convert_PStoAS`, to convert from practical salinity (-) to absolute salinity (g/kg)

`convert_AStoPS`, to convert from absolute salinity (g/kg) to practical salinity (-)

### Examples

``````sw_svel(t = 40, S = 40, p = 10:20, method = "UNESCO")

# Check value UNESCO
sw_svel(t = 40, S = 40, p = 1000, method = "UNESCO")  # 1731.995
sw_svel(t = 0, S = 40, p = 0, method = "UNESCO")      # 1455.8

sw_svel(t = 40, S = 25, p = 1000, method = "UNESCO")  # 1719.2
sw_svel(t = 40, S = 25, p = 0, method = "UNESCO")     # 1553.4
sw_svel(t = 0, S = 25, p = 0, method = "UNESCO")      # 1435.8

# Check value Gibbs
sw_svel(S = 35.7, t = 25.5, p = 102.3)              # 1552.93372863425

``````

marelac documentation built on Sept. 25, 2023, 5:06 p.m.