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Workspace Method abs_lineshapeDefine

Description

Set the lineshape for all calculated lines.

Sets the lineshape function. Beside the lineshape function itself, you
also have so select a forefactor and a frequency cutoff. The
forefactor is later multiplied with the lineshape function.

The cutoff frequency is used to make lineshapes finite in frequency,
the response outside the cutoff is set to zero, and the lineshape
value at the cutoff frequency is subtracted from the overall lineshape
as a constant offset. This ensures that the lineshape goes to zero at
the cutoff frequency without a discontinuity.

We generate only one copy of the lineshape settings. Absorption
routines check for this case and use it for all species.

The allowed values for the input parameters are:

shape:
   no_shape:                 no specified shape
   Doppler:                  Doppler lineshape
   Lorentz:                  Lorentz lineshape
   Voigt_Kuntz3:             Kuntz approximation to the Voigt lineshape,
                             accuracy > 2x10^(-3)
   Voigt_Kuntz4:             Kuntz approximation to the Voigt lineshape,
                             accuracy > 2x10^(-4)
   Voigt_Kuntz6:             Kuntz approximation to the Voigt lineshape,
                             accuracy > 2x10^(-6)
   Voigt_Drayson:            Drayson approximation to the Voigt lineshape
   Rosenkranz_Voigt_Drayson: Rosenkrantz oxygen absortion with overlap correction
                             on the basis of Drayson routine
   Rosenkranz_Voigt_Kuntz6 : Rosenkrantz oxygen absortion with overlap correction
                             on the basis of Kuntz routine, accuracy > 2x10^(-6)
   CO2_Lorentz:              Lorentz multiplied with Cousin's chi factors
   CO2_Drayson:              Drayson multiplied with Cousin's chi factors
   Faddeeva_Algorithm_916:   Faddeeva function based on Zaghloul, M.R. and
                             A.N. Ali (2011).  Implementation by Steven G. Johnson
                             under the MIT License (attainable through
                             http://ab-initio.mit.edu/Faddeeva)

forefactor:
   no_norm:                  1
   quadratic:                (f/f0)^2
   VVH:                      (f*tanh(h*f/(2k*T))) / (f0*tanh(h*f0/(2k*T)))

cutoff:
    -1:                      no cutoff
   <Number>:                 positive cutoff frequency in Hz

Authors: Axel von Engeln, Stefan Buehler

Synopsis

Variables