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)

• G_Function: Leaf angle distribution function

canopy_sw_rt_beer_lambert(
    Ω::FT,
    SW_d:FT,
    α_leaf::FT,
    LAI::FT,
    K::FT,
    α_soil::FT
)

Computes the absorbed, reflected, and transmitted flux fractions by radiation band.

This applies the Beer-Lambert law, which is a function of 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 fractions.

canopy_sw_rt_two_stream(
    G::FT,
    Ω::FT,
    n_layers::UInt64,
    SW_d::FT,
    α_leaf::FT,
    τ_leaf::FT,
    LAI::FT,
    K::FT,
    θs::FT,
    α_soil::FT,
    frac_diff::FT,
)

Computes the absorbed, reflected, and transmitted flux fractions by 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 fractions.

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 (G).

Canopy.canopy_radiant_energy_fluxes!(p::NamedTuple,
                                     s::Union{PrognosticGroundConditions,PrognosticSoilConditions},
                                     canopy,
                                     radiation::PrescribedRadiativeFluxes,
                                     earth_param_set::PSE,
                                     Y::ClimaCore.Fields.FieldVector,
                                     t,
                                    ) where {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,
                              ground::PrescribedGroundConditions
                              canopy,
                              radiation::PrescribedRadiativeFluxes,
                              earth_param_set::PSE,
                              Y::ClimaCore.Fields.FieldVector,
                              t,
                             ) where {PSE}

Computes and stores the net long and short wave radiation, in W/m^2, over all bands, absorbed by the canopy when the canopy is run in standalone mode, with only a :canopy model as a prognostic component, with PrescribedGroundConditions.

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