Radiative Transfer

BeerLambertParameters{FT <: AbstractFloat}

The required parameters for the Beer-Lambert radiative transfer model.

• α_PAR_leaf: PAR leaf reflectance (unitless)

• α_NIR_leaf: NIR leaf reflectance

• ϵ_canopy: Emissivity of the canopy

• Ω: Clumping index following Braghiere (2021) (unitless)

• λ_γ_PAR: Typical wavelength per PAR photon (m)

• λ_γ_NIR: Typical wavelength per NIR photon (m)

• G_Function: Leaf angle distribution function

compute_absorbances(
    RT::BeerLambertModel{FT},
    PAR,
    NIR,
    LAI,
    K,
    α_soil_PAR,
    α_soil_NIR,
    _,
    _,
)

Computes the PAR and NIR absorbances, reflectances, and tranmittances for a canopy in the case of the Beer-Lambert model. The absorbances are a function of the radiative transfer model, as well as the magnitude of incident PAR and NIR radiation in moles of photons, the leaf area index, the extinction coefficient, and the soil albedo in the PAR and NIR bands. Returns a NamedTuple of NamedTuple, of the form: (; par = (; refl = , trans = , abs = ), nir = (; refl = , trans = , abs = ))

compute_absorbances(
    RT::TwoStreamModel{FT},
    PAR,
    NIR,
    LAI,
    K,
    α_soil_PAR,
    α_soil_NIR,
    θs,
    frac_diff,
)

Computes the PAR and NIR absorbances, reflectances, and tranmittances for a canopy in the case of the Beer-Lambert model. The absorbances are a function of the radiative transfer model, as well as the magnitude of incident PAR and NIR radiation in moles of photons, the leaf area index, the extinction coefficient, and the soil albedo in the PAR and NIR bands.

This model also depends on the diffuse fraction and the zenith angle. Returns a NamedTuple of NamedTuple, of the form: (; par = (; refl = , trans = , abs = ), nir = (; refl = , trans = , abs = ))

plant_absorbed_pfd(
    RT::BeerLambertModel{FT},
    SW_IN:FT,
    α_leaf::FT,
    LAI::FT,
    K::FT,
    α_soil::FT
)

Computes the absorbed, reflected, and transmitted photon flux density in terms of mol photons per m^2 per second for a radiation band.

This applies the Beer-Lambert law, which is a function of incident radiation (SW_IN; moles of photons/m^2/), leaf reflectance (α_leaf), the extinction coefficient (K), leaf area index (LAI), and the albedo of the soil (α_soil).

Returns a tuple of reflected, absorbed, and transmitted radiation in mol photons/m^2/s.

plant_absorbed_pfd(
    RT::TwoStreamModel{FT},
    α_leaf,
    SW_IN::FT,
    LAI::FT,
    K::FT,
    τ_leaf,
    θs::FT,
    α_soil::FT,
)

Computes the absorbed, transmitted, and reflected photon flux density in terms of mol photons per m^2 per second for a radiation band.

This applies the two-stream radiative transfer solution which takes into account the impacts of scattering within the canopy. The function takes in all parameters from the parameter struct of a TwoStreamModel, along with the incident radiation, LAI, extinction coefficient K, soil albedo from the canopy soil_driver, solar zenith angle, and τ.

Returns a tuple of reflected, absorbed, and transmitted radiation in mol photons/m^2/s.

extinction_coeff(ld::FT,
                 θs::FT) where {FT}

Computes the vegetation extinction coefficient (K), as a function of the sun zenith angle (θs), and the leaf angle distribution (ld).

Canopy.canopy_radiant_energy_fluxes!(p::NamedTuple,
                                     s::PrognosticSoil{FT},
                                     canopy,
                                     radiation::PrescribedRadiativeFluxes,
                                     earth_param_set::PSE,
                                     Y::ClimaCore.Fields.FieldVector,
                                     t,
                                    ) where {FT, PSE}

In standalone mode, this function computes and stores the net long and short wave radition, in W/m^2, absorbed by the canopy.

In integrated mode, we have already computed those quantities in lsm_radiant_energy_fluxes!, so this method does nothing additional.

LW and SW net radiation are stored in p.canopy.radiative_transfer.LW_n and p.canopy.radiative_transfer.SW_n.

canopy_radiant_energy_fluxes!(p::NamedTuple,
                              s::PrescribedSoil,
                              canopy,
                              radiation::PrescribedRadiativeFluxes,
                              earth_param_set::PSE,
                              Y::ClimaCore.Fields.FieldVector,
                              t,
                             ) where {PSE}

Computes and stores the net long and short wave radition, in W/m^2, absorbed by the canopy when the canopy is run in standalone mode, with a PrescribedSoil conditions.

LW and SW net radiation are stored in p.canopy.radiative_transfer.LW_n and p.canopy.radiative_transfer.SW_n.