Characteristics and Behavior of Atmospheric Aerosols; Application to Prediction of Infrared Extinction

摘要

This report describes the characteristics of atmospheric aerosols in terms of their effect on infrared radiation extinction. The aerosol properties are described in terms of the globally uniform background aerosol component and the component of the aerosol that varies on the time scale of hours to a few days. The various atmospheric processes that influence the properties of both components are described, including production, transport and removal. This report discusses the effect of aerosol chemical composition and atmospheric relative humidity on aerosol physical properties and relates these effects to extinction of near and far infrared radiation. These various aerosol characteristics are related to the aerosol models in the LOWTRAN Atmospheric Transmittance Code. The presence or absence of the sea-salt aerosol is presented as the most important factor influencing the variability in aerosol infrared extinction. This report presents a method of selecting the most appropriate LOWTRAN aerosol model for a given situation. The method is based on airmass history analysis.