Nonequilibrium radiative transfer in structured atmospheres

The nonequilibrium middle and upper atmosphere are very dynamic regions that are structured vertically and horizontally by the presence of persistent temperature inversion layers and by the passage of both atmospheric gravity waves and transient frontal disturbances or bores. The infrared emissions from this part of the atmosphere are already typically not in local thermodynamic equilibrium (LTE) and are further perturbed by the presence of this pervasive atmospheric structure. The inevitable result is highly structured atmospheric emissions that reflect the structure of the atmosphere. Understanding the structure of the atmosphere is essential to understanding the structure of the radiation that it emits. At the same time understanding how atmospheric structure perturbs atmospheric radiation provides a means to sense the perturbing atmospheric processes remotely. We examine methods to calculate the LTE/non-LTE radiative response to temporal and spatial variations of the atmosphere and give examples of applications. We also compare our results with existing field data. Finally, we discuss a proposed new NASA optical/infrared experiment (Waves Explorer) to sense atmospheric gravity waves remotely from earth orbit on a global basis and characterize their sources.

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