ARTS built-in documentation server
Workspace Method surfaceMapToLinearPolarisation
Convert surface RT properties to a linear polarisation.
The properties converted are surface_emission and surface_rmatrix.
This method allows to set the surface properties to match a specific
linear polarisation for scalar calculation (stokes_dim=1). If you want
this, you have to call the method(s) setting up the surface RT
properties with stokes_dim set to 2, 3 or 4. This Stokes dimension
is below called local_stokes_dim.
The polarisation to apply is selected by *pol_angle*. This angle is
defined as in sensor_pol (i.e. 0 and 90 equal V and H, respectively).
If local_stokes_dim was set to 2, *surface_rmatrix is assumed to have
[ (rv+rh)/2 (rv-rh)/2;
(rv-rh)/2 (rv+rh)/2 ],
while if local_stokes_dim was set to 3 or 4, the mapping involves
several transformation matrices. The later case covers also couplings
between V/H and +-45 deg, and the mapping is described in the ARTS
theory guide, in section "Rotated modified Stokes vector".
In general it should suffice to set local_stokes_dim to 2, that gives
slightly faster calculations. A local_stokes_dim of 3 handles any case
Authors: Patrick Eriksson