HITRAN data
Last updated: 23JAN22
HITRAN spectroscopic line parameters are required for both the Scene Generator
and Level 2 Processing stages of the Cubemap End-to-End Simulator.
The data are available, free, from
the hitran.org web-site but first it is
necessary
to register as a user.
Once registered, to download the data ...
- Go to https://hitran.org and log in
- Select Data Access from the
menu, then Line-by-line, then go through
the following screens ...
- 1. Select Molecules
- Click on Select All then
click on 2.Select Isotopologues >
- 2. Select Isotopologues
- Just click on 3.Select wavenumber/wavelength range >,
which has the effect of selecting all isotopologues apart from a couple of
obscure CO2 variants
- 3. Select Wavenumber/Wavelength Range
- Just click on 4.Select output options
> which will select
the entire dataset. If you want a smaller dataset (c.half-size), set the range to
νmin=1100 cm-1 and
νmax=17500 cm-1 which covers the actual range required
for HIROS+HSDI spectra.
- 4. Select or Create Output Format
- This should already highlight
.par (160 chars) as the default, so
just click on 5. Start Data Search
>. After a minute or two ...
- Search Results
- Click on the .par file ('Output transitions data...') which will be 1.2 GB
in size (or about half that if you've restricted the spectral range).
This will start the actual file download
- Rename the downloaded file to something more meaningful, eg 'hitran_2020.par'
The RFM (within the Scene Generator)
can use the .par file directly, although it is numerically more
efficient to convert the data to RFM binary form using the Fortran program hitbin
MORSE (within the L2 Processor)
can currently only read HITRAN data in binary
form.