Latest: RFM v5.20 (20 Apr 2023)


The RFM is a line-by-line radiative transfer model developed at
AOPP, Oxford University, originally under an ESA contract to provide reference spectral calculations for the Envisat/MIPAS instrument. It was largely built on GENLN2 algorithms. It has subsequently been expanded into a general purpose code suitable for a variety of different spectroscopic calculations.

The main algorithm description is in the 2017 paper listed below under Publications

The original code was written in FORTRAN77 but in 2018 RFM v5 was released, rewritten in FORTRAN90. The current version is compatible with HITRAN 2020 and GEISA 2015 (as well as older versions).

RFM maintenance and development is currently supported by the UK National Centre for Earth Observation (NCEO).

The main design features are

I'll consider adding other features that people would find useful, including combinations of features which are currently not allowed. Just let me know, along with any bug-reports.

To get a copy, email me with a brief statement on what you're planning on using it for (which helps me to anticipate future user requirements) and I'll email you the source code.

Anu Dudhia ( )

Spectroscopic Data

The RFM is designed to use the three main types of HITRAN spectroscopic data Additional HITRAN data sets such as HITEMP (line data) and UV (cross-section data) can also used, with some care.

GEISA is an alternative to HITRAN, providing similar line and cross-section data but in a different format. While the RFM cannot use GEISA data directly, local software is provided to convert these to HITRAN format.

Things the RFM can handle...

(Not all of these are compatible - see
User's Manual for the full list of 'flags').

Things the RFM cannot handle...


If you publish anything involving the RFM in the scientific literature I do not expect to be a co-author, or even consulted. However, I would appreciate it if you sent me a reference for the final publication since it helps me obtain funding for RFM support.

If you want to cite the RFM, the following is recommended:

Dudhia, A
The Reference Forward Model (RFM)
Journal of Quantitative Spectroscopy and Radiative Transfer
186 (2017) 243–253

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