sasktran2.optical.XsecAbsorber

class sasktran2.optical.XsecAbsorber(source: str | Path | list[str] | list[Path])

Bases: OpticalProperty

Cross section absorber loaded from HITRAN fixed-width format files.

This absorber loads cross section data from .xsc files and performs interpolation in temperature (linear) and uses the nearest pressure level. Wavenumber interpolation uses zero padding outside the available range.

Parameters:

source (str or list of str or Path) – Can be: - Path to a single .xsc file - Path to a folder containing .xsc files - List of paths to .xsc files

Examples

Load from a folder:

>>> absorber = XsecAbsorber("/path/to/hitran/xsec/CCl4")

Load from a single file:

>>> absorber = XsecAbsorber("/path/to/hitran/xsec/CCl4_v1.xsc")

Load from multiple files:

>>> absorber = XsecAbsorber(["/path/to/file1.xsc", "/path/to/file2.xsc"])

__init__(source: str | Path | list[str] | list[Path])

Methods

__init__(source)
atmosphere_quantities(atmo, **kwargs)	Calculate optical quantities for a given atmosphere.
cross_section_derivatives(wavelengths_nm, ...)
cross_sections(wavelengths_nm, altitudes_m, ...)
from_lbl_database(species_name)	Load cross sections from the LBLRTM database for a given species.
optical_derivatives(atmo, **kwargs)	Calculate optical derivatives for a given atmosphere.

atmosphere_quantities(atmo, **kwargs)

Calculate optical quantities for a given atmosphere.

Parameters:

• atmo (Atmosphere) – Atmosphere object containing temperature and pressure profiles

• **kwargs – Must include wavenumbers_cminv as an array

Returns:

Object containing cross sections and other optical properties

Return type:

OpticalQuantities

classmethod from_lbl_database(species_name: str) → XsecAbsorber

Load cross sections from the LBLRTM database for a given species.

This method reads the FSCDXS index file to determine which cross section files to load for the requested species, then loads them.

Parameters:

species_name (str) –

Name of the species. Case insensitive.

Supported species: ACET, ACETICACI, BRO, C2CL2F4 (F114), C2CL3F3 (F113), C2CLF5 (F115), C2F6, C2HCl2F3CF2, CCL2FCH3, CCL4, CCLF3 (F13), CF3CH2CF3, CF3CH3, CF4 (F14), CFH2CF3, CH2F2, CH3CCLF2, CH3CHF2, CH3CN, CHCl2C2F5, CHCl2CF3, CHCL2F, CHClF2, CHClFCF3, CHF2CF3, CHF2CH2CF3, CHF3, CLONO2, F11, F12, FURAN, GLYCOLALD, HCHO, HNO3, HNO4, ISOP, N2O5, NF3, NO2, PAN, PROPENE, SF6, SO2

Returns:

XsecAbsorber instance with the loaded cross section data

Return type:

XsecAbsorber

Raises:

ValueError – If the species name is not found in the LBLRTM database

Examples

>>> absorber = XsecAbsorber.from_lbl_database('CCL4')
>>> absorber = XsecAbsorber.from_lbl_database('HNO3')
>>> absorber = XsecAbsorber.from_lbl_database('f11')  # Case insensitive

optical_derivatives(atmo, **kwargs)

Calculate optical derivatives for a given atmosphere.

Parameters:

• atmo (Atmosphere) – Atmosphere object containing temperature and pressure profiles

• **kwargs – Must include wavenumbers_cminv as an array

Returns:

Dictionary with “temperature_k” key containing temperature derivatives

Return type:

dict