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Workspace Method surfaceFastem
Description
Usage of FASTEM together with MC and DOIT.
The recommended way to use FASTEM is by iySurfaceFastem, but that
is not always possible, such as when using MC and DOIT. This is the
case as those scattering methods use surface_rtprop_agenda,
while iySurfaceFastem fits with iy_surface_agenda. This WSM solves
this by allowing FASTEM to be used inside surface_rtprop_agenda.
However, FASTEM is here used in an approximative way. For a correct
usage of FASTEM, the atmospheric transmittance shall be calculated
for the position and direction of concern, but this is not possible
together with DOIT and MC. Instead, the transmittance is an input
to the method, and must either be pre-calculated or set to a
representative value.
See iySurfaceFastem, for further details on the special input
arguments.
Authors: Patrick Eriksson
Synopsis
| surfaceFastem( | surface_los, surface_rmatrix, surface_emission, atmosphere_dim, stokes_dim, f_grid, rtp_pos, rtp_los, surface_skin_t, salinity, wind_speed, wind_direction, transmittance, fastem_version ) |
Variables
| OUT | surface_los | (Matrix) | Downwelling radiation directions to consider in surface reflection. |
| OUT | surface_rmatrix | (Tensor4) | The reflection coefficients for the directions given by surface_los to the direction of interest. |
| OUT | surface_emission | (Matrix) | The emission from the surface. |
| IN | atmosphere_dim | (Index) | The atmospheric dimensionality (1-3). |
| IN | stokes_dim | (Index) | The dimensionality of the Stokes vector (1-4). |
| IN | f_grid | (Vector) | The frequency grid for monochromatic pencil beam calculations. |
| IN | rtp_pos | (Vector) | Position of a radiative transfer point. |
| IN | rtp_los | (Vector) | Line-of-sight at a radiative transfer point. |
| IN | surface_skin_t | (Numeric) | Surface skin temperature. |
| GIN | salinity | (Numeric, Default: 0.035) | Salinity, 0-1. That is, 3% is given as 0.03. |
| GIN | wind_speed | (Numeric) | Wind speed. |
| GIN | wind_direction | (Numeric, Default: 0) | Wind direction. See futher above. |
| GIN | transmittance | (Vector) | Transmittance along path of downwelling radiation. A vector with the same length as f_grid. |
| GIN | fastem_version | (Index, Default: 6) | The version of FASTEM to use. |