colour.scattering_cross_section

colour.scattering_cross_section(wavelength, CO2_concentration=300, temperature=288.15, avogadro_constant=6.02214179e+23, n_s=<function air_refraction_index_Bodhaine1999>, F_air=<function F_air_Bodhaine1999>)[source]

Returns the scattering cross section per molecule \(\sigma\) of dry air as function of wavelength \(\lambda\) in centimeters (cm) using given \(CO_2\) concentration in parts per million (ppm) and temperature \(T[K]\) in kelvin degrees following Van de Hulst (1957) method.

Parameters:
  • wavelength (numeric or array_like) – Wavelength \(\lambda\) in centimeters (cm).
  • CO2_concentration (numeric or array_like, optional) – \(CO_2\) concentration in parts per million (ppm).
  • temperature (numeric or array_like, optional) – Air temperature \(T[K]\) in kelvin degrees.
  • avogadro_constant (numeric or array_like, optional) – Avogadro’s number (molecules \(mol^{-1}\)).
  • n_s (object) – Air refraction index \(n_s\) computation method.
  • F_air (object) – \((6+3_p)/(6-7_p)\), the depolarisation term \(F(air)\) or King Factor computation method.
Returns:

Scattering cross section per molecule \(\sigma\) of dry air.
Return type:

numeric or ndarray

Warning

Unlike most objects of colour.phenomena.rayleigh module, colour.scattering_cross_section() expects wavelength \(\lambda\) to be expressed in centimeters (cm).

References

[BWDS99], [Wik01d]

Examples

>>> scattering_cross_section(555 * 10e-8)  # doctest: +ELLIPSIS
4.6613309...e-27