calculate_cp: Calculate the solubility of dissolved oxygen

In Centre-for-Marine-Applied-Research/strings: Compile, Format, and Visualize Sensor String Data

Calculate the solubility of dissolved oxygen

Description

Calculate the solubility of dissolved oxygen based on temperature, salinity and barometric pressure, following the equations in Benson and Krause 1984 or Garcia and Gordon 1992.

Usage

calculate_cp(
  dat.wide,
  Sal = NULL,
  P_atm = NULL,
  method = "garcia-gordon",
  return.factors = FALSE
)

Arguments

dat.wide	Dataframe with at least one column: Temperature. Corresponding salinity (psu) and pressure (atm) data may be included in columns Salinity and Pressure. Additional columns will be ignored and returned.
Sal	A single value of salinity (psu). This value must be specified if there is no Salinity column in dat.wide. Default is Sal = NULL. Note: if Sal is specified when there is a Salinity column in dat.wide, the function will stop with an error.
P_atm	A single value of barometric pressure (atm). This value should be specified if there is no Pressure column in dat.wide. Default is P_atm = NULL. Note: if P_atm is specified when there is a Pressure column in dat.wide, function will stop with an error.
method	Equation to use to calculate dissolved oxygen solubility. Options are method = "garcia-gordon" (the default) and method = "benson-krause".
return.factors	Logical parameter. If TRUE the function returns dat.wide with additional columns for the parameters used to calculate F_s (salinity correction factor), F_p (pressure correction factor), and C_p (DO solubility). If FALSE, the function returns dat.wide with additional column(s) Salinity, Pressure, and C_p.

Details

Solubility of dissolved oxygen (mg/L) is calculated using the equations in Benson and Krause 1984, or the or Garcia and Gordon 1992 refit. These equations should only be used when 0 < Temperature < 40 degrees Celcius, 0 < Salinity < 40 PSU and 0.5 < Pressure < 1.1 atm.

Results from this function should closely match those from the USGS DOTABLES Table B (output from GG method may differ in the second decimal place) at https://water.usgs.gov/water-resources/software/DOTABLES/.

For more information see Equations 24 and 32, and Table 2 from Benson and Krause 1984 or Equation 8 and Table 1 from Garcia and Gordon 1992.

For the Garcia and Gordon equation, coefficients from the first column of Table 1 were used. Conversion factor of 1.42905 was applied to convert from cm^3/dm^3 (mL/L) to mg/L (USGS 2011).

References

Benson, Bruce B., Krause, Daniel, (1984), The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere, Limnology and Oceanography, 3, doi: 10.4319/lo.1984.29.3.0620.

Garcia, H., and L. Gordon (1992), Oxygen solubility in seawater: Better fitting equations, Limnol. Oceanogr., 37(6).

USGS. Change to Solubility Equations for Oxygen in Water. Technical Memorandum 2011.03. USGS Office of Water Quality, 2011.

See Also

Other Dissolved Oxygen: DO_pressure_correction(), DO_salinity_correction(), calculate_DO_concentration(), calculate_DO_percent_saturation()

Centre-for-Marine-Applied-Research/strings documentation built on Aug. 21, 2023, 8 a.m.