Aerosol Altitude Localization

Because aerosols exhibit considerable variation in location, height, time, and constitution, different concepts exist for describing aerosol loading in the atmosphere. Models for the vertical variability of atmospheric aerosols are generally broken into a number of distinct layers. In each of these layers, a dominant physical mechanism determines the type, number density, and size distribution of particles. Generally accepted layer models consist of the following [33,34]: a boundary layer that includes aerosol mixing goes from 0 to 2—2.5 km elevation, a free tropospheric region from 2.5 to 7—8 km, a stratospheric layer from 8 to 30 km, and layers above 30 km composed mainly of particles that are extraterrestrial in origin such as meteoric dust [21].

The average thickness of the aerosol-mixing region is approximately 2—2.5 km. Within this region, one would expect the aerosol concentration to be influenced strongly by conditions at ground level. Consequently, aerosols in this region display the highest variability with meteorological conditions, climate,

etc. [34—43].

In Reference 16, various studies have been compiled, and a global climatology of aerosol optical properties for Arctic, Antarctic, desert, continental, urban, and maritime regions developed. Based on these aerosol distributions, they have modeled aerosol optical properties on a global scale.

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