CO2 Flux Atmosphere Lake

Combine a caller Henry equilibrium with measured dissolved CO2 and piston velocity into signed atmosphere–lake flux; positive is emission, negative uptake, and carbonate speciation is external.

Description

Air-water CO2 exchange depends on dissolved concentration relative to atmospheric equilibrium.

Air-water CO2 exchange depends on dissolved concentration relative to atmospheric equilibrium. A supplied Henry coefficient and piston velocity convert that difference into signed flux.^[1]

The tool returns equilibriumCo2MolesPerM3, signedCo2FluxMolesPerM2Day, signedLakeCo2KgPerDay. The computation uses supplied observations and parameters rather than acquiring measurements.

When to use CO2 Flux Atmosphere Lake

Use this for the following task: Combine a caller Henry equilibrium with measured dissolved CO2 and piston velocity into signed atmosphere–lake flux; positive is emission, negative uptake, and carbonate speciation is external. Prepare observations and calibration parameters on the same unit and reporting basis.

How to use CO2 Flux Atmosphere Lake and understand its results

Prepare the measured quantities and supplied model parameters. Match the units and align paired lists before calculating.
Enter dissolvedCo2MolesPerM3, atmosphericCo2PartialPressurePa, henryMolesPerM3Pa, pistonVelocityMPerDay, lakeAreaM2, co2MolarMassGramsPerMole according to the field table, then run the tool.
Read equilibriumCo2MolesPerM3, signedCo2FluxMolesPerM2Day, signedLakeCo2KgPerDay. Use the calculation below to interpret the selected mean or the model’s signs, units and comparison flags.
Review the supplied assumptions and calibration before comparing or reporting the result.

Input field	Meaning	Value type and bounds	Requirement
dissolvedCo2MolesPerM3	Dissolved co2 moles per m3	number	Required
atmosphericCo2PartialPressurePa	Atmospheric co2 partial pressure pa	number	Required
henryMolesPerM3Pa	Henry moles per m3 pa	number	Required
pistonVelocityMPerDay	Piston velocity m per day	number	Required
lakeAreaM2	Lake area m2	number	Required
co2MolarMassGramsPerMole	Co2 molar mass grams per mole	number	Required

Supply nonnegative dissolved concentration, partial pressure and piston velocity with positive Henry coefficient, area and molar mass. Return equilibrium concentration, areal molar flux and lake mass flux.

equilibrium=HenryCoefficient×partialPressure; flux=pistonVelocity×(dissolved−equilibrium); lake kg/day=flux×area×molarMass/1000

The symbols and boundary conditions refer to the supplied fields and the implementation described above.

Output field	Meaning	Value type
equilibriumCo2MolesPerM3	Equilibrium co2 moles per m3	number
signedCo2FluxMolesPerM2Day	Signed co2 flux moles per m2 day	number
signedLakeCo2KgPerDay	Signed lake co2 kg per day	number

json

{
  "input": {
    "dissolvedCo2MolesPerM3": 12,
    "atmosphericCo2PartialPressurePa": 100,
    "henryMolesPerM3Pa": 0.1,
    "pistonVelocityMPerDay": 0.5,
    "lakeAreaM2": 100,
    "co2MolarMassGramsPerMole": 44
  },
  "output": {
    "equilibriumCo2MolesPerM3": 10,
    "signedCo2FluxMolesPerM2Day": 1,
    "signedLakeCo2KgPerDay": 4.4
  }
}

Limitations and assumptions

Positive flux means emission and negative flux uptake. Carbonate speciation, temperature dependence of Henry’s coefficient and spatial representativeness are supplied or assessed externally.

Numerical inputs must be finite. Input-shape and calculation checks do not establish measurement quality or the validity of a supplied calibration.

Alternative or Complementary methods

Choose Piston Velocity Gas Exchange when you need its operation: Scale a measured reference gas-transfer piston velocity by a supplied Schmidt-number power relation; does not infer wind dependence or gas concentration gradients. Choose Methane Bubbling Emission Estimate for the complementary operation: Normalize trap-measured bubble methane by dry-gas ideal-law correction and summed area×time; negative blank-corrected estimates are preserved as nondetection evidence, not clamped emissions.

Background reference: Estimating lake-atmosphere CO2 exchange.

References

Estimating lake-atmosphere CO2 exchange — U.S. Geological Survey

Similar or alternative tools

Piston Velocity Gas Exchange
Scale a measured reference gas-transfer piston velocity by a supplied Schmidt-number power relation; does not infer wind dependence or gas concentration gradients.
Methane Bubbling Emission Estimate
Normalize trap-measured bubble methane by dry-gas ideal-law correction and summed area×time; negative blank-corrected estimates are preserved as nondetection evidence, not clamped emissions.