computations on cloud growth related to the seeding of tropical cumuli

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  • 1 University of California at Los Angeles
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A statistical study has been conducted investigating the possible cloud growth effects due to heat released when supercooled water is converted to ice. Calculations are made of the heights to which cloud tops would rise assuming that the supercooled water is converted to ice at − 10C (the seeded case) or at − 30C (the unseeded case). The clouds suffer a loss in buoyancy due to entrainment and the weight of the condensate. Sixty-two cases are treated for soundings from St. Martins Island during August of 1962. The results of this study are compared to those of a similar study for Flagstaff, Arizona, during the summers of 1961, 1962 and 1963. The results imply that spectacular height increases due to seeding can be expected, but that such cases are relatively infrequent. Specific observations of cloud growth due to seeding are noted, but can only be considered as consistent with these concepts rather than verifying them. The factors important for the seeding effect and the conditions which produce them are also examined. Despite the simplicity of the model, it is felt that the computed height differences qualitatively represent a reasonable measure of the potential for cloud dynamics changes from seeding.

1 Now attending Florida State University, Tallahassee, Fla.

A statistical study has been conducted investigating the possible cloud growth effects due to heat released when supercooled water is converted to ice. Calculations are made of the heights to which cloud tops would rise assuming that the supercooled water is converted to ice at − 10C (the seeded case) or at − 30C (the unseeded case). The clouds suffer a loss in buoyancy due to entrainment and the weight of the condensate. Sixty-two cases are treated for soundings from St. Martins Island during August of 1962. The results of this study are compared to those of a similar study for Flagstaff, Arizona, during the summers of 1961, 1962 and 1963. The results imply that spectacular height increases due to seeding can be expected, but that such cases are relatively infrequent. Specific observations of cloud growth due to seeding are noted, but can only be considered as consistent with these concepts rather than verifying them. The factors important for the seeding effect and the conditions which produce them are also examined. Despite the simplicity of the model, it is felt that the computed height differences qualitatively represent a reasonable measure of the potential for cloud dynamics changes from seeding.

1 Now attending Florida State University, Tallahassee, Fla.

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