sasktran2.optical.HenyeyGreenstein

class sasktran2.optical.HenyeyGreenstein(db_filepath: Path | None = None, db: Dataset | None = None, max_num_moments: int = 128)

Bases: OpticalDatabase

An optical property that uses a Henyey-Greenstein phase function. I.e., the phase function is defined from a single asymmetry parameter g.

The input should either be a path to a netCDF file containing the database, or an xarray Dataset.

The dataset must contain the following variables:

• xs_total: Total extinction cross-section in [m^2]

• ssa: Single scattering albedo (unitless)

• asymmetry_parameter: Asymmetry parameter (unitless)

with Coordinates: - wavelength_nm: Wavelength in [nm]

The variables may have additional dimensions corresponding to different parameters (e.g., temperature).

Parameters:

• db_filepath (Path | None, optional) – Path to a netCDF file containing the database, by default None

• db (xr.Dataset | None, optional) – An xarray Dataset containing the database, by default None

__init__(db_filepath: Path | None = None, db: Dataset | None = None, max_num_moments: int = 128) → None

An optical property that uses a Henyey-Greenstein phase function. I.e., the phase function is defined from a single asymmetry parameter g.

The input should either be a path to a netCDF file containing the database, or an xarray Dataset.

The dataset must contain the following variables:

• xs_total: Total extinction cross-section in [m^2]

• ssa: Single scattering albedo (unitless)

• asymmetry_parameter: Asymmetry parameter (unitless)

with Coordinates: - wavelength_nm: Wavelength in [nm]

The variables may have additional dimensions corresponding to different parameters (e.g., temperature).

Parameters:

• db_filepath (Path | None, optional) – Path to a netCDF file containing the database, by default None

• db (xr.Dataset | None, optional) – An xarray Dataset containing the database, by default None

Methods

__init__([db_filepath, db, max_num_moments])	An optical property that uses a Henyey-Greenstein phase function.
atmosphere_quantities(atmo, **kwargs)
cross_section_derivatives(wavelengths_nm, ...)
cross_sections(wavelengths_nm, altitudes_m, ...)
from_parameters(wavelength_nm, xs_total, ssa, g)	Create a Henyey-Greenstein optical database from parameter arrays.
optical_derivatives(atmo, **kwargs)

classmethod from_parameters(wavelength_nm: array, xs_total: array, ssa: array, g: array, max_num_moments: int = 128) → HenyeyGreenstein

Create a Henyey-Greenstein optical database from parameter arrays. Note that these parameters are thus geometry independent, i.e., do not depend on altitude or location.

Parameters:

• wavelength_nm (np.array) – Wavelength in [nm]

• xs_total (np.array) – Total extinction cross-section in [m^2]

• ssa (np.array) – Single scattering albedo (unitless)

• g (np.array) – Asymmetry parameter (unitless)

• max_num_moments (int, optional) –

  Maximum number of moments to use, should be set higher than the number of streams

  used in the calculation. by default 128