The Effect of Utilizing Empirically Derived Values of Coalescence Efficiency in a Microphysical Cloud Model

Abstract

A one-dimensional eulerian warm cloud model which incorporates the effects of stochastic coalescence, drop breakup, and vertical water mass transfer is used to determine the effect of empirically derived values of the coalescence efficiency. A constant vertical updraft profile is used to artifically produced liquid water increases and to produce a realistic restraint for hydrometeor fallout. Although most microphysical models have assumed coalescence efficiency to be equal to one, the recent work of Whelpdale and List, and Levin et al., indicate that coalescence efficiency is closely related to droplet/drop size ratio P, and decreases with increasing P. Starting with an initial droplet spectrum for a tropical cumulus which produces rain within 20 minutes when using a coalescence efficiency of one, comparative runs are made using the empirical data.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1974
Accession Number
AD0786699

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  • Paul M. Tag

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  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Classification
  • Clouds
  • Condensation
  • Cumulus Clouds
  • Differential Equations
  • Efficiency
  • Equations
  • Hydrometeors
  • Mass Spectra
  • Precipitation
  • Rain
  • Raindrops
  • Rainfall
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  • Spectra
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  • Atmospheric Remote Sensing.
  • Computational Modeling and Simulation
  • Mathematics or Statistics