pyrad.solvers.two_stream module

pyrad.solvers.two_stream.adding(R_direct, R_diffuse, T_direct, T_diffuse, T_pure, direct_surface_albedo, diffuse_surface_albedo)[source]
Calculates the shortwave upward and downward fluxes using the “adding” method.

An overview of this method is provided in the appendix of https://doi.org/10.1029/94JD01310.*/

Parameters

  • R_direct – Layer reflectivity for a direct beam (layer).

  • R_diffuse – Layer reflectivity for a diffuse beam (layer).

  • T_direct – Layer transmittance for a direct beam (layer).

  • T_diffuse – Layer transmittance for a diffuse beam (layer).

  • T_pure – Amount of incident radiation that passes through each layer without being absorbed or scattered (layer).

  • direct_surface_albedo – Surface albedo for a direct beam.

  • diffuse_surface_albedo – Surface albedo for a diffuse beam.

Returns

Total upward reflectance at each level (level). T: Total downward transmittance at each level (level).

Return type

R

pyrad.solvers.two_stream.delta_eddington(optical_depth, single_scatter_albedo, asymmetry_factor, cosine_zenith)[source]
Uses the delta-Eddington approximation to calculate the reflectivity and transmittance

of a plane-parallel atmospheric layer. The specificform of the Eddinton approximation used here is described in https://doi.org/10.1175/1520-0469(1980)037<0630:TSATRT>2.0.CO;2.

Parameters

  • optical_depth – Optical depth.

  • single_scatter_albedo – Single-scatter albedo.

  • asymmetry_factor – Asymmetry factor.

  • cosine_zenith – Cosine of the beam zenith angle.

Returns

Reflectivity. T: Transmittance. T_pure: Amount of incident radiation that passes through without being

absorbed or scattered.

Return type

R

pyrad.solvers.two_stream.eddington(optical_depth, single_scatter_albedo, asymmetry_factor, cosine_zenith)[source]
Uses the Eddington approximation to calculate the reflectivity and transmittance

of a plane-parallel atmospheric layer. The specificform of the Eddinton approximation used here is described in https://doi.org/10.1175/1520-0469(1980)037<0630:TSATRT>2.0.CO;2.

Parameters

  • optical_depth – Optical depth.

  • single_scatter_albedo – Single-scatter albedo.

  • asymmetry_factor – Asymmetry factor.

  • cosine_zenith – Cosine of the beam zenith angle.

Returns

Reflectivity. T: Transmittance. T_pure: Amount of incident radiation that passes through without being

absorbed or scattered.

Return type

R

pyrad.solvers.two_stream.scaling(optical_depth, single_scatter_albedo, asymmetry_factor)[source]
Performs the scaling required by the delta-Eddington method. The scaling

parameters are described in https://doi.org/10.1175/1520-0469(1976)033<2452:TDEAFR>2.0.CO;2.

Parameters

  • optical_depth – Optical depth.

  • single_scatter_albedo – Single-scatter albedo.

  • asymmetry_factor – Asymmetry factor.

Returns

Scaled optical depth. omega: Scaled single-scatter albedo. g: Scaled asymmetry factor.

Return type

tau