Anomalous snowfall caused by natural-draft cooling towers

by Lloyd Randall Koenig

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Reports from several sources, including satellite images, suggest that under appropriate circumstances cooling-tower plumes from large electric power generating facilities can generate nontrivial amounts of snow. Tabulation of a number of aerial observations yields the criteria of temperature colder than -13 degrees centigrade and saturation vapor density deficit less than 0.5 gram per cubic meter in the vicinity of the plume for production of such anomalous snow. Numerical simulation with a model describing cloud microphysical processes in considerable detail offers theoretical verification of these empirical criteria. Although the model could be improved by incorporating interactive dynamics and a method to regulate efficiently the introduction of new ice-particle categories, it is in its present form capable of producing much useful information on the microphysical processes within plumes and plume interaction with existing clouds.

This report is part of the RAND Corporation Note series. The note was a product of the RAND Corporation from 1979 to 1993 that reported other outputs of sponsored research for general distribution.

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