README.md

arts-crossfit

ARTS HITRAN cross section absorption model

Calculate cross sections with the model

1. Download the precalculated coefficients files from the arts-xml-data package and put them in the coefficients/ directory.

   To generate the coefficients yourself, see section "Generate model coefficients" below.

2. Run the example script.

   scripts/Xsec_Calculate.py
   

   Creates a plot of CFC-11 crossections in plots/Xsecs/.

Generate model coefficients

1. Download Hitran cross section data and molecule headers into designated folders

   cd data/HitranXsec/
   curl -O https://hitran.org/data/xsec/xss.tar.gz
   tar -zxf xss.tar.gz
   cd ../HitranMoleculeHeaders/
   wget --no-parent -nd -r -A '*.json' https://hitran.org/suppl/xsec/molecule_headers/
   cd -
   

2. Convert cross section data to json format

   scripts/Xsec_ConvertHitranToJson.py
   

3. Generate harmonized data

   scripts/Xsec_DefineBandsAndHarmonizeData.py
   

   Choose option 0 to use the predefined band configuration.

4. Generate model coefficients

   scripts/Xsec_CalculateFitCoefficients.py -f
   

   The -f option generates optional diagnostic figures in plots/SPECIES/.

   Use -p X to speed up the calculation by using X cores in parallel.

   The XML data files are stored in coefficients/.