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Workspace Method DisortCalcIrradiance

Description

Interface to the DISORT scattering solver (by Stamnes et al.).
for running flux (irradiance) calculations

It provides the irradiance field from a scalar
1D scattering solution assuming a plane-parallel atmosphere (flat
Earth). Only totally randomly oriented particles are allowed.
Refraction is not taken into account. Only Lambertian surface
reflection is handled.

*nstreams* is the number of polar angles taken into account
internally in the scattering solution and for the angular integration.
*nstreams* determines the angular resolution, hence the accuracy,
of the scattering solution. The more anisotropic the bulk scattering
matrix, the more streams are required. The computational burden
increases approximately linearly with *nstreams*. The default value
(6) is sufficient for most flux calculations.

Some auxiliary quantities can be obtained. Auxiliary
quantities are selected by disort_aux_vars and returned by disort_aux.
Valid choices for auxiliary data are:
 "Layer optical thickness": Matrix [f_grid, size of p_grid - 1] layer optical
                              thickness.
 "Single scattering albedo": Matrix [f_grid, size of p_grid - 1] layer single"
                               scattering albedo.
 "Direct downward spectral irradiance": Matrix [f_grid, p_grid]. 
                               Direct downward spectral irradiance.
                               Zero, if no star is present. 
 "dFdtau": Matrix [f_grid, p_grid]. Flux divergence in optical 
                               thickness space.

Authors: Manfred Brath

Synopsis

DisortCalcIrradiance( spectral_irradiance_field, disort_aux, atmfields_checked, atmgeom_checked, scat_data_checked, propmat_clearsky_agenda, gas_scattering_agenda, atmosphere_dim, pnd_field, t_field, z_field, vmr_field, p_grid, lat_true, lon_true, refellipsoid, scat_data, stars, f_grid, stokes_dim, z_surface, surface_skin_t, surface_scalar_reflectivity, gas_scattering_do, stars_do, disort_aux_vars, nstreams, Npfct, only_tro, quiet, emission, intensity_correction )

Variables

OUTspectral_irradiance_field(Tensor5)Spectral irradiance field.
OUTdisort_aux(ArrayOfMatrix)Auxilary data to the output of the DisortCalc-Methods.
INatmfields_checked(Index)OK-flag for atmospheric grids and (physical) fields.
INatmgeom_checked(Index)OK-flag for the geometry of the model atmosphere.
INscat_data_checked(Index)OK-flag for scat_data.
INpropmat_clearsky_agenda(Agenda)Agenda calculating the absorption coefficient matrices.
INgas_scattering_agenda(Agenda)Agenda calculating gas scattering extinction and phase matrix.
INatmosphere_dim(Index)The atmospheric dimensionality (1-3).
INpnd_field(Tensor4)Particle number density field.
INt_field(Tensor3)The field of atmospheric temperatures.
INz_field(Tensor3)The field of geometrical altitudes.
INvmr_field(Tensor4)VMR field.
INp_grid(Vector)The pressure grid.
INlat_true(Vector)Latitudinal geolocation for 1D and 2D data.
INlon_true(Vector)Longitudinal geolocation for 1D and 2D data.
INrefellipsoid(Vector)Reference ellipsoid.
INscat_data(ArrayOfArrayOfSingleScatteringData)Array of single scattering data.
INstars(ArrayOfStar)Array of Star.
INf_grid(Vector)The frequency grid for monochromatic pencil beam calculations.
INstokes_dim(Index)The dimensionality of the Stokes vector (1-4).
INz_surface(Matrix)The surface altitude.
INsurface_skin_t(Numeric)Surface skin temperature.
INsurface_scalar_reflectivity(Vector)Surface reflectivity, assuming it can be described as a scalar value.
INgas_scattering_do(Index)Flag to activate gas scattering.
INstars_do(Index)Flag to activate the star(s).
INdisort_aux_vars(ArrayOfString)Selection of quantities for disort_aux .
GINnstreams(Index, Default: 6)Number of polar angle directions (streams) in DISORT solution (must be an even number).
GINNpfct(Index, Default: 181)Number of angular grid points to calculate bulk phase function on (and derive Legendre polynomials from). If <0, the finest za_grid from scat_data will be used.
GINonly_tro(Index, Default: 0)Set to 1 if the scattering data is just of TRO type. Has effect only if Npfct > 3 or Npfct<0, but then leads to much faster calculations.
GINquiet(Index, Default: 0)Silence C Disort warnings.
GINemission(Index, Default: 1)Enables blackbody emission. Set to zero, if no Emission e. g. like in visible regime for earth is needed
GINintensity_correction(Index, Default: 1)Enables intensity correction. Importantant for low number of streams. Set to zero, if problems encounter or using a high number of streams (>30)