esfofo: Equation of State from Fofonoff 1985

In kevans27/aqeco: Basic Functions for Aquatic Ecologists

Description

Returns the density of water for a given pressure, salinity, and temperature. This series of functions is from Fofonoff (1985). Depth is scaled to pressure using equation 23 from Dukowicz (2001). Pressure as a function of altitude is derived from the ideal gas law using a scale height of 8.4km.

I am assuming that water is incompressible. This is almost a fair assumption but not quite (think 0.1 percent errors for high altitudes [>1km]).

Usage

esfofo(Sal, Temp, Dep, Alt)

Arguments

Sal	Salinity in units of PSS 78 (practical salinity scale 78)
Temp	Temperature in Celsius
Dep	Depth which you're interested in in meters.
Alt	Altitude of your observation site in meters.

Value

Returns density in units of kilograms per cubic meter.

Author(s)

Kate Evans, University of Montana/Flathead Lake Biological Station

References

Fofonoff, N. P. (1985). Physical properties of seawater: A new salinity scale and equation of state for seawater. Journal of Geophysical Research, 90(C2), 3332. https://doi.org/10.1029/JC090iC02p03332

Dukowicz, J. K. (2001). Reduction of Density and Pressure Gradient Errors in Ocean Simulations. Journal of Physical Oceanography, 31(7), 1915–1921. https://doi.org/10.1175/1520-0485(2001)031<1915:RODAPG>2.0.CO;2

Examples

#Salt water with salinity of 35, at 25 C, 200m depth, and sea level.
density <- esfofo(35, 25, 200, 0)
density = 1024.20

#Fresh water with salinity of 0, at 15 C, water surface, and 1000m altitude.
density <- esfofo(0, 15, 0, 1000)
density = 999.0963

kevans27/aqeco documentation built on May 16, 2019, 4:08 a.m.