Formation of Absorption Bands in a Scattering Atmosphere.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Formation of Absorption Bands in a Scattering Atmosphere. Irvine, William M. Abstract Within the wavelength region of an absorption band formed in a nonemitting planetary atmosphere the absorption coefficient will be a rapidly changing function of frequency. Many spectral lines may be contained within the bandwidth of the detector, and the attenuation will in general not be exponential. Let In be the specific intensity of n-times scattered radiation in a nonabsorbing layer, and let p~ be the probability density of the optical paths of photons contributing to In. On the assumption that the scattering properties of the atmosphere are constant across the band, the specific intensity I is expressed in terms of In, ~n, and the transmittance relative to the continuum ~ of a sample of the atmosphere. The mean geometric path (l~ traveled by reflected or transmitted light may be expressed in terms of In and the first moments (Xa~ of pa. Knowledge of (l~ is important in the determination of the abundance of an absorbing constituent. The (Xa~ provide an estimate of the absorption suffered by n-times scattered light. The probabilities p~ may be expressed by an inverse Laplace transform involving the In. The results for n = t and n =2 for finite atmospheres and for all n when the layer is semi-infinite are obtained explicitly. The (Xa~ may be expressed directly in terms of In and 3In/~T (r is the optical thickness of the atmosphere). This work will be described in detail in a forthcoming article in the Bulletin of the A stronomical Institutes of the Netherlands. Publication: The Astronomical Journal Pub Date: 1963 DOI: 10.1086/109120 Bibcode: 1963AJ.....68R.538I full text sources ADS |