The Numerical Modeling of Ice-Phase Cloud Seeding Effects in a Warm-Base Cloud: Preliminary Results

Authors

  • H D Orville Institute of Atmospheric Sciences South Dakota School of Mines and Technology Rapid City, South Dakota
  • F J Kopp Institute of Atmospheric Sciences South Dakota School of Mines and Technology Rapid City, South Dakota
  • R D Farley Institute of Atmospheric Sciences South Dakota School of Mines and Technology Rapid City, South Dakota
  • R B Hoffman Institute of Atmospheric Sciences South Dakota School of Mines and Technology Rapid City, South Dakota

Abstract

A numerical simulation of a warm-base cloud in the southeastern United States has resulted in a vigorous cloud development, much in agreement with observations by radar and aircraft on that day (20 July 1986). The case has been rerun with all of the ice processes turned off and vigorous growth still occurs. The natural ice processes enhance the cloud cell development and produce about 12% more precipitation. Simulated cloud seeding of the natural cloud case [testing both silver iodide (Agl) and solid carbon dioxide (C02)] produces about 5% less precipitation from this large convective cloud. The same sounding is used but with decreased vapor flux, to produce a smaller warm-base cloud. Simulated cloud seeding of that cloud results in 12% increases in precipitation, illustrating that the dynamics of the cloud are important for determining the seeding results.

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Scientific Papers