Study of the theoretical behavior of ammonium sulfate aerosols in the vicinity of cloud base
Date
1993-08-25
Authors
Stevens, Bjorn, author
Journal Title
Journal ISSN
Volume Title
Abstract
The theoretical behavior of hygroscopic aerosols in an environment typical of cloud base and sub-cloud regions is reviewed. Particular attention is paid to an evaluation of the appropriateness of a variety of assumptions typically made in the treatment of aerosol to cloud drop transitions. It is found that the ideal assumptions associated with the solute modification to surface vapor pressure involves significant errors for the small CCN. While small hygroscopic aerosols are well characterized by their equilibrium size, the slow response times of larger aerosols make them poor candidates for description by equilibrium theory. Non equilibrium effects are quantified as a function of size. The activation process is also considered for a variety of specified supersaturation fields. In general, the activation of hygroscopic aerosols is not instantaneous, the lag time associated with activation is particularly important for the larger aerosols. The implications of these findings on numerical cloud models is discussed.
Description
August 25, 1993.
Rights Access
Subject
Cloud physics
Aerosols