RFM Examples

Nadir Microwave Spectra

22NOV20


Description

Nadir-viewing microwave spectrum.

*FLG section specifies

NAD flag
Downward viewing through a plane parallel atmosphere;
SFC flag
Mandatory with the NAD flag, indicating that surface contributions are included. In the absence of any *SFC section in the driver table (as in this example) default values are assumed: surface temperature matches that of the lowest atmospheric temperature and surface emissivity=1
RJT flag
Output the Rayleigh-Jeans temperature spectrum (proportional to radiance, and commonly used in the microwave region)
GHZ flag
Specify spectral units are in GHz rather than cm-1. This applies to the numbers in the *SPC section as well as the output spectral file.
VVW flag
Apply the Van Vleck-Weisskopf correction to the Voigt lineshape, again commonly used in the microwave region.

In the *SPC section the resolution of 0.005 GHz corresponds to just under 6000 points per cm-1. For limb-viewing you would need something finer to capture lines limited by Doppler broadening to approx 10-6 x frequency,

Driver Table

*HDR
11MAR19 RFM Example: nadir microwave
*FLG
   NAD SFC RJT GHZ VVW 
*SPC
  50 70 0.005
*GAS
  O2 H2O
*ATM
   ../atm/usa.atm
*SEC
  1.0
*HIT
  ../hit/hitran_2012.bin
*END

Output Files

Output Spectrum

[plot.pro]