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Workspace Method surfaceLambertianSimple

Description

Creates variables to mimic a Lambertian surface, ignoring the
azimuthal dimension.

A lambertian surface can be characterised solely by its
reflectivity, here taken from surface_scalar_reflectivity.

The down-welling radiation field is estimated by making calculations
for *np* directions. The range of zenith angles ([0,90]) is divided
in an equidistant manner. The values for surface_rmatrix are
assuming a constant radiance over each zenith angle range. See AUG.

Default is to select the zenith angles for sensor_los to be placed
centrally in the grid ranges. For example, if *np* is set to 9,
down-welling radiation will be calculated for zenith angles = 
5, 15, ..., 85. The position of these angles can be shifted by
*za_pos*. This variable specifies the fractional distance inside the
ranges. For example, a *za_pos* of 0.7 (np still 9) gives the angles
7, 17, ..., 87.
Any aziumuth angle in sensor_los is set to 0.

Local thermodynamic equilibrium is assumed, which corresponds to
that the reflection and emission coefficients "add up to 1".

Authors: Patrick Eriksson

Synopsis

surfaceLambertianSimple( surface_los, surface_rmatrix, surface_emission, f_grid, stokes_dim, atmosphere_dim, rte_los, surface_skin_t, surface_scalar_reflectivity, np, za_pos )

Variables

OUTsurface_los(Matrix)Directions for which to calculate downwelling radiation when considering a surface reflection.
OUTsurface_rmatrix(Tensor4)The reflection coefficients for the directions given by surface_los to the direction of interest.
OUTsurface_emission(Matrix)The emission from the surface.
INf_grid(Vector)The frequency grid for monochromatic pencil beam calculations.
INstokes_dim(Index)The dimensionality of the Stokes vector (1-4).
INatmosphere_dim(Index)The atmospheric dimensionality (1-3).
INrte_los(Vector)A line-of-sight for radiative transfer calculations.
INsurface_skin_t(Numeric)Surface skin temperature.
INsurface_scalar_reflectivity(Vector)Surface reflectivity, assuming it can be described as a scalar value.
GINnp(Index)Number of zenith angles for calculation of down-welling radition.
GINza_pos(Numeric, Default: 0.5)Position of angle in surface_los inside ranges of zenith angle grid. See above.