Ring Effect

These classes are used to calculate the ‘Ring spectrum’ which is used to account for inelastic atmospheric scattering in DOAS retrievals.

Rotational Raman Cross Sections

class skdoas.ring.rotational_raman_lines.RotationalRamanLines

class skdoas.ring.rotational_raman_lines.RotationalRamanLinesN2

Calculates N2 rotation Raman lines according to Chance and Spurr (1997) using the data supplied with Chance and Martin (2017) on the Oxford University Press website (http://global.oup.com/booksites/content/9780199662104/data/).

References

K. V. Chance and R. J. D. Spurr. Ring effect studies: Rayleigh scattering, including molecular parameters for rotational Raman scattering, and the Fraunhofer spectrum. Applied Optics, 36(21):5224-5230, 1997.

Kelly Chance and Randall V. Martin. Spectroscopy & Radiative Transfer of Planetary Atmospheres. Oxford University Press, Oxford, United Kingdom, 2017.

class skdoas.ring.rotational_raman_lines.RotationalRamanLinesO2

Calculates O2 rotation Raman lines according to Chance and Spurr (1997) using the data supplied with Chance and Martin (2017) on the Oxford University Press website (http://global.oup.com/booksites/content/9780199662104/data/).

References

K. V. Chance and R. J. D. Spurr. Ring effect studies: Rayleigh scattering, including molecular parameters for rotational Raman scattering, and the Fraunhofer spectrum. Applied Optics, 36(21):5224-5230, 1997.

Kelly Chance and Randall V. Martin. Spectroscopy & Radiative Transfer of Planetary Atmospheres. Oxford University Press, Oxford, United Kingdom, 2017.

class skdoas.ring.rotational_raman_lines.RotationalRamanLinesHan

Base class for RRS ring effect cross section computation following Han et al. The base class should not be used directly.

Objects derived from this base class can be used to calculate the cross section of a particular energy level transition within the target molecule. It can also be used to calculate cross section as a equation of wavelength.

These classes are depreciated, superceded by RotationalRamanLinesN2 and RotationalRamanLinesO2 which do not use the approximations used here.

References

D. Han, L. Chen, L. Su, J. Tao, S. Li, C. Yu, Y. Zhang, and B. He. A convolution algorithm to calculate differential cross sections of the ring effect in the earth’s atmosphere based on rotational raman scattering. Science China Earth Sciences, 54(9):1407-1412, 2011.

K. V. Chance and R. J. D. Spurr. Ring effect studies: Rayleigh scattering, including molecular parameters for rotational Raman scattering, and the Fraunhofer spectrum. Applied Optics, 36(21):5224-5230, 1997.

class skdoas.ring.rotational_raman_lines.RotationalRamanLinesN2Han

class skdoas.ring.rotational_raman_lines.RotationalRamanLinesO2Han

Ring Spectrum

class skdoas.ring.ring_spectrum.RingSpectrum(solar_spectrum_wavelength: numpy.ndarray, solar_spectrum_irradiance: numpy.ndarray, n2_cross_sections: skdoas.ring.rotational_raman_lines.RotationalRamanLines, o2_cross_sections: skdoas.ring.rotational_raman_lines.RotationalRamanLines)

Calculates the ring spectrum from rotational Raman scattering of O2 and N2 particles. For use in DOAS retrievals.

Parameters

• solar_spectrum_wavelength (np.ndarray) – Array of wavelengths corresponding to the irradiance data.

• solar_spectrum_irradiance (np.ndarray) – Solar top-of-atmosphere irradiance data.