On the different approaches of Rayleigh optical depth determination

• Published in: Advances in space research Vol. 44; no. 9; pp. 1058 - 1066
• Main Authors: Srivastava, Shailendra S., Vyas, N.K., Rai, Jagdish, Kartikeyan, B.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 02.11.2009; Elsevier
• Subjects: Astronomy; Depolarization factor; Earth, ocean, space; Exact sciences and technology; External geophysics; Mie scattering; Rayleigh scattering; Size parameter; Rayleigh scattering; Mie scattering; Depolarization factor; Size parameter; Refractive index; Rotational transition; Space research; Molecule scattering; Depolarization; Vibrational transition; Trend analysis; Angular momentum; Models; Radiative transfer; Optical thickness
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/j.asr.2009.06.015

Rayleigh optical depth is an integral part of many radiative transfer problems. This paper discusses different elements and approaches of its determination. Then, it presents a method, which ensures more realistic estimate of Rayleigh optical depth by using refractive index and depolarization factor (including rotational Raman lines) adjusted according to the state and composition of the atmosphere. It is based on the published experimental and theoretical results. The Rayleigh optical depth calculations are compared with the Elterman’s model calculations for trend analysis purpose. Rayleigh optical depths are found to be around 3.4% lower than previous researchers, as they ignored the constraints of conservation of angular momentum in the rotational/vibrational transitions of the molecules during scattering.