RFM Driver Table Sections

*FIN Section: Resolution of Fine Mesh Calculation

24NOV17

Type
Secondary Section - depends on FIN Flag.

Description
User-specified Resolution for Fine Mesh Calculation when used in conjunction with ILS convolution (to replace default value of 0.0005 cm-1).

Format
Single field
FieldTypeDescriptionRange
RESFIN R*8 (<1) Wavenumber [cm-1] (1/MAXFIN):1.0 (RFM v5: no limit)
Or Frequency [GHz] if GHZ Flag set
I (>1) N.Pts/cm-1 1:MAXFIN (RFM v5: no limit)

Notes
  1. Without any spectral convolutions (no ILS or AVG Flags) the RFM generates spectrally sampled output at the resolution RESSPC specified in the *SPC section of the driver table, so this is also fine mesh resolution for calculations. However, if any spectral averaging is required, either by an explicit instrument line shape convolution (ILS Flag) or using the AVG Flag, the fine mesh resolution for the calculations defaults to 0.0005 cm-1 (set by 1/DEFFIN in rfmcon.inc, rfmcon_dat.f90 for RFM v5) irrespective of the output resolution, unless modified by the value supplied here.
  2. The RFM default value of 0.0005 cm-1 is appropriate for mid-infrared limb-viewing calculations, and is set by the requirement to capture the area of Doppler-broadened lines (typical half-width 0.001 cm-1). For nadir-viewing infrared, 0.001 cm-1 is considered adequate. The Doppler width narrows in proportion to wavenumber, so for microwave limb-viewing a value of 30 000 is required.
  3. A warning message is issued if the specified resolution appears inadequate for the highest required tangent height.
  4. The allowed range of RESFIN is (1/MAXFIN):MAXFIN where MAXFIN is specified in rfmsiz.inc (see Memory Size) (For RFM v5.0 there is no MAXFIN limit)

Example
*FIN
   1000    ! Perform fine mesh calculation at 1000pts/cm-1 (0.001 cm-1 spacing)
Bugs
Bug#103 (Fixed v4.34)