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A method is presented for retrieving pressure, temperature, and ozone mixing ratio profiles from multilevel high resolution earthlimb emission data taken in the spectral region near the CO(2)Q-branch at 791.5 cm(-1). Theory is developed for the construction of a retrieval algorithm which brings the magnitudes of calculated and measured CO(2) and O(3) features into agreement by adjusting a hydrostatic trial atmosphere having one fixed reference pressure. It is shown that overlap between the CO(2) and O(3) features can be used to determine the correct reference pressure. The method is examined using simulations to demonstrate the retrieval of vertical profiles of pressure, temperature, and ozone mixing ratio in the stratosphere. Numerical studies of the effects of uncertainties in line parameters and instrument calibration errors are also presented.

A plane-parallel approximation using FASCODE to calculate upward and downward IR flux density and angle-averaged radiance is described and tested against results that account for planetary curvature. The method is further developed to calculate the excitation of NO(v = 1) due to absorption of upwelling radiation in the earth's atmosphere. The algorithm is applied to a standard set of atmospheric models, in addition to typical and extreme desert atmospheric models which are included to maximize the effect. The results of this work show that upwelling radiation typically contributes <2.5% to the total NO(v = 1) excitation in the midstratosphere rises to ~5% at 50 km and becomes increasingly significant at higher altitudes. It is shown that in the mesosphere excitation due to upwelling and solar radiation become important compared to the dominant processes, thermal collisions, and chemical excitation. An approximate technique utilizing meteorological data, namely, tropospheric temperature, pressure, and humidity profiles, is developed to estimate the excitation of NO(v = 1) in the middle atmosphere. This technique would facilitate the retrieval of the NO mixing ratio from earthlimb emission data, as might be obtained from a satellite-borne limb sounding experiment, since it could be used to approximate the contribution of upwelling radiation to the NO(v = 1) non-LTE vibrational temperature efficiently.

It is commonly observed that natural multiple-scattering media such as sand and soils become noticeably darker when wet. The primary reason for this is that changing the medium surrounding the particles from air to water decreases their relative refractive index, hence increases the average degree of forwardness of scattering as determined by the asymmetry parameter (mean cosine of the scattering angle). As a consequence, incident photons have to be scattered more times before reemerging from the medium and are, therefore, exposed to a greater probability of being absorbed. A simple theory incorporating this idea yields results that are in reasonable agreement with the few measurements available in the literature, although there are differences. Our measurements of the reflectance of sand wetted with various liquids are in reasonably good agreement with the simple theory. We suggest that the difference between reflectances of wet and dry surfaces may have implications for remote sensing.