RFM Flags

REX Flag: Include Rayleigh Extinction

23SEP17

Introduced with RFM v4.33
Enabled
Incorporate extinction due to Rayleigh Scattering into spectral calculations.

Disabled
No Rayleigh extinction

Restrictions
Incompatible with TAB Flag.

Notes
  1. Rayleigh extinction is only significant for wavenumbers >3000 cm-1 (wavelengths < 3 µm) - regions where the thermal emission of the atmosphere is negligible
  2. Enabling the REX flag internally causes 'air' to be added to the user-specified list of absorbers from the *GAS, so may cause the MAXGAS dimension (specified in file rfmsiz.inc) to be exceeded (see Array size errors) (not an issue for RFM v5)
  3. The extinction cross-section calculation is based on Bodhaine et al (1999) appropriate for the earth's atmosphere. For other atmospheres, refractivity (subroutine refrac.for) and depolarisation (subroutine kingdf.for) might have to be modified, (refrac_fnc.f90, spcrex_fnc.f90 in RFM v5.0)

Bugs
[none reported]