Soil Water Parameterizations

AbstractImpedanceFactor{FT <: AbstractFloat}

NoImpedance{FT} <: AbstractImpedanceFactor{FT}

A model to indicate to dependence on ice for the hydraulic conductivity.

IceImpedance{FT} <: AbstractImpedanceFactor{FT}

The necessary parameters for the empirical impedance factor due to ice.

Fields

• Ω

  Empirical coefficient from Hansson 2014.

impedance_factor(
    imp::NoImpedance{FT},
    θ_i::FT,
    θ_l::FT,
) where {FT}

Returns the impedance factor when no effect due to ice is desired. Returns 1.

The other arguments are included to unify the function call.

impedance_factor(
    imp::IceImpedance{FT},
    θ_i::FT,
    θ_l::FT,
) where {FT}

Returns the impedance factor when an effect due to the fraction of ice is desired.

AbstractViscosityFactor{FT <: AbstractFloat}

ConstantViscosity{FT} <: AbstractViscosityFactor{FT}

A model to indicate a constant viscosity - independent of temperature - factor in hydraulic conductivity.

TemperatureDependentViscosity{FT} <: AbstractViscosityFactor{FT}

The necessary parameters for the temperature dependent portion of hydraulic conductivity.

Fields

• γ

  Empirical coefficient

• T_ref

  Reference temperature

viscosity_factor(
    vm::ConstantViscosity{FT},
    T::FT,
) where {FT}

Returns the viscosity factor when we choose no temperature dependence, i.e. a constant viscosity. Returns 1.

T is included as an argument to unify the function call.

viscosity_factor(
    vm::TemperatureDependentViscosity{FT},
    T::FT,
) where {FT}

Returns the viscosity factor when we choose a TemperatureDependentViscosity.

AbstractMoistureFactor{FT <:AbstractFloat}

MoistureDependent{FT} <: AbstractMoistureFactor{FT} end

Moisture dependent moisture factor.

MoistureIndependent{FT} <: AbstractMoistureFactor{FT} end

Moisture independent moisture factor.

moisture_factor(
    mm::MoistureDependent{FT},
    hm::vanGenuchten{FT},
    S_l::FT,
) where {FT}

Returns the moisture factor of the hydraulic conductivy assuming a MoistureDependent and van Genuchten hydraulic model.

moisture_factor(
    mm::MoistureDependent{FT},
    hm::BrooksCorey{FT},
    S_l::FT,
) where {FT}

Returns the moisture factor of the hydraulic conductivy assuming a MoistureDependent and Brooks/Corey hydraulic model.

moisture_factor(
    mm::MoistureDependent{FT},
    hm::Haverkamp{FT},
    S_l::FT,
) where {FT}

Returns the moisture factor of the hydraulic conductivy assuming a MoistureDependent and Haverkamp hydraulic model.

moisture_factor(mm::MoistureIndependent{FT},
                hm::AbstractHydraulicsModel{FT},
                S_l::FT,
) where {FT}

Returns the moisture factor in hydraulic conductivity when a MoistureIndependent model is chosen. Returns 1.

Note that the hydraulics model and S_l are not used, but are included as arguments to unify the function call.

AbstractsHydraulicsModel{FT <: AbstractFloat}

Hydraulics model is used in the moisture factor in hydraulic conductivity and in the matric potential. The single hydraulics model choice sets both of these.

vanGenuchten{FT} <: AbstractHydraulicsModel{FT}

The necessary parameters for the van Genuchten hydraulic model; defaults are for Yolo light clay.

Fields

• n

  Exponent parameter - used in matric potential

• α

  used in matric potential. The inverse of this carries units in the expression for matric potential (specify in inverse meters).

• m

  Exponent parameter - determined by n, used in hydraulic conductivity

BrooksCorey{FT} <: AbstractHydraulicsModel{FT}

The necessary parameters for the Brooks and Corey hydraulic model.

Defaults are chosen to somewhat mirror the Havercamp/vG Yolo light clay hydraulic conductivity/matric potential.

Fields

• ψb

  ψ_b - used in matric potential. Units of meters.

• m

  Exponent used in matric potential and hydraulic conductivity.

Haverkamp{FT} <: AbstractHydraulicsModel{FT}

The necessary parameters for the Haverkamp hydraulic model for Yolo light clay.

Note that this only is used in creating a hydraulic conductivity function, and another formulation for matric potential must be used.

Fields

• k

  exponent in conductivity

• A

  constant A (units of cm^k) using in conductivity. Our sim is in meters

• n

  Exponent parameter - using in matric potential

• α

  used in matric potential. The inverse of this carries units in the expression for matric potential (specify in inverse meters).

• m

  Exponent parameter - determined by n, used in hydraulic conductivity

hydraulic_conductivity(
    impedance::AbstractImpedanceFactor{FT},
    viscosity::AbstractViscosityFactor{FT},
    moisture::AbstractMoistureFactor{FT},
    hydraulics::AbstractHydraulicsModel{FT},
    θ_i::FT,
    porosity::FT,
    T::FT,
    S_l::FT,
) where {FT}

Returns the hydraulic conductivity.

effective_saturation(
    porosity::FT,
    ϑ_l::FT
) where {FT}

Compute the effective saturation of soil.

ϑ_l is defined to be zero or positive. If ϑ_l is negative, hydraulic functions that take it as an argument will return imaginary numbers, resulting in domain errors. Exit in this case with an error.

pressure_head(
    model::AbstractHydraulicsModel{FT},
    porosity::FT,
    S_s::FT,
    ϑ_l::FT,
) where {FT}

Determine the pressure head in both saturated and unsaturated soil.

hydraulic_head(z,ψ)

Return the hydraulic head.

The hydraulic head is defined as the sum of vertical height z and pressure head ψ; meters.

matric_potential(
        model::vanGenuchten{FT},
        S_l::FT
) where {FT}

Compute the van Genuchten function for matric potential.

matric_potential(
        model::Haverkamp{FT},
        S_l::FT
) where {FT}

Compute the van Genuchten function as a proxy for the Haverkamp model matric potential (for testing purposes).

matric_potential(
        model::BrooksCorey{FT},
        S_l::FT
) where {FT}

Compute the Brooks and Corey function for matric potential.

volumetric_liquid_fraction(
    ϑ_l::FT,
    porosity::FT,
) where {FT}

Compute the volumetric liquid fraction from the porosity and the augmented liquid fraction.