On the Interpretation of Atmospheric Turbidity Measurements

• Published in: Journal of the atmospheric sciences 1976-05, Vol.33 (5), p.794-797
• Main Authors: Hänel, Gottfried, Bullrich, Kurt
• Format: Article
• Language: English
• ISSN: 0022-4928; 1520-0469
• DOI: 10.1175/1520-0469(1976)033<0794:OTIOAT>2.0.CO;2

The paper relates the optical thickness of all aerosol particles along a vertical path through the atmosphere to the vertical profiles of the particle number density and relative humidity. The effects of multiple scattering and surface albedo on the optical thickness are neglected because cases involving extremely high turbidity are not considered. The model adopted assumes three different types of aerosol appearing in three main layers of the atmosphere: lower troposphere, upper troposphere, and lower stratosphere. For the lower atmosphere, continental aerosol and maritime aerosol are considered. Model calculations indicate that the largest contribution to the total optical thickness comes from the lower troposphere and that for relative humidities higher than 90% within a thin layer of about 80 m thickness, the main contribution to the total optical thickness comes from this layer. Stratospheric aerosol does not contribute significantly to the total optical thickness except for those cases where the particle numbers around 18 km are larger than about 2 per cu cm.