HITRAN/HITEMP

May (2021) Hajime Kawahara

See “Computing CO cross section using HITRAN (opacity calculator = LPF)” for tutorial to compute a cross section profile using HITRAN/HITEMP.

Molecular Database

An example to use HITRAN / HITEMP from exojax is like that.

>>> from exojax.utils.grids import wavenumber_grid
>>> from exojax.spec import moldb
>>> nus,wav,res=nugrid(22880.,23000.,1000,unit="AA")
>>> mdbCO=moldb.MdbHit('.database/05_HITEMP2019.par.bz2',nus)
bunziping

HITEMP H2O and CO2

For H2O and CO2, HITEMP provides multiple par files. To use those files, provide the directory path for moldb.MdbHit as follows.

>>> mdbH2O=moldb.MdbHit('.database/01_HITEMP2010',nus)
>>> mdbCO2=moldb.MdbHit('.database/02_HITEMP2010',nus)

extract option

extract=True in moldb.MdbHit extracts the opacity data in the wavenumber range of nus with margin. Theforefore it can reduce the use of DRAM. It may be useful for large databases such as CH4.

>>> mdbCH4=moldb.MdbHit('.database/06_HITEMP2020.par.bz2',nus,extract=True)

This creates a new directory (such as 6101.281269066504_6108.7354917532075_1.0 ) and the extracted data and header files (06_HITEMP2020.header and 06_HITEMP2020.par ) in it:

ls .database

06_HITEMP2020.par
6101.281269066504_6108.7354917532075_1.0:
06_HITEMP2020.header  06_HITEMP2020.par

Basic Quantities

These are the basic quantities of MdbHit.

quantity	instance	unit	np/jnp
line center	nu_lines	cm-1	np
line center	dev_nu_lines	cm-1	jnp
lower state energy	elower	cm-1	jnp
natural broadening	gamma_natural	cm-1	jnp
air pressure broadening	gamma_air	cm-1	jnp
self broadning	gamma_self	cm-1	jnp
Einstein coefficient	A	s-1	jnp
reference line strength	Sij0	cm	np
log_e Sij0	logsij0		jnp
statistical weight	gpp		jnp
temperature exponent	n_air		jnp

Collision Induced Absorption (CIA)

Collision Induced Absorption (CIA) is one of the important continuum in exoplanet/brown dwarfs atmosphere. HITRAN provides the CIA files . To load the CIA file, use contdb.

>>> from exojax.spec import contdb
>>> cdbH2H2=contdb.CdbCIA('.database/H2-H2_2011.cia',nus)

See “CIA coefficient” for tutorial.