Scattering of emitted radiation from inhomogeneous and nonisothermal layers

A parametric study is performed for the exiting monochromatic intensities scattered from finite, plane-parallel, inhomogeneous layers that are driven solely by a distribution of thermal sources. Intensities are obtained by invariantly imbedding the standard and thermal scattering functions. The single scattering albedo ω and the Henyey-Greenstein phase-function parameter g are varied independently, and both linear and exponential profiles are considered. Linear temperature profiles are used, including temperature inversions. The resulting intensities I(μ), μ representing the direction cosine of propagation, are discussed from a remote sensing point of view. For an isothermal and homogeneous medium, the gross characteristics of I(μ) represented by its overall slope I(0)/I(1), mean value (magnitude), and an interior maximum value can be related to the total optical depth t₀, ω, and g, respectively. For a homogeneous medium, linearly decreasing (in the line of sight) temperature profiles tend to obscure the g information and decrease the apparent optical depth. On the other hand, linearly increasing temperature profiles tend to retain g information and increase the apparent optical depth. Temperature inversion profiles give intensities very similar to those for purely linear profiles. Linear and exponential variations of both ω and g for constant temperatures give similar intensity fields. Results for a variation in g can be reproduced fairly well with an average g value. This cannot be done, however, for ω profiles.