WMOD00462

• Contract/Permit #: 87-1999
• Title: Development of Empirical Equations of Ice Crystal Growth Microphysics for Modeling Analysis - Final Report
• Date: 9/1/1988
• Weather Modification - Doc Type: Report

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ABSTRACT

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Experimental data on ice crystal growth measured during recent

investigations in a supercooled cloud tunnel that suspended ice crystals for

time periods up to 30 min at the University of Utah have been analyzed.

These experimental investigations previously generated unique data sets of

mass, dimensions and fall velocity as a function of time under different

temperatures and removed some obstacles caused by the tack of proper

experimental data that have hindered cloud microphysical research.

The analysis in this thesis was set out to fulfill at least the following four

goals using the data sets from the previous experiments. First, some specific

features of microphysical theories have been verified with the experimental

data. Second, time . dependent equations of mass, dimensions and fall

velocity applicable to different ragimes of growth have been developed by

considering the measured data and the functional styles of theories and not by

merely obtaining a set of best filting polynomials. Third, an empirical

equation was derived by similar means to express the aerodynamic behavior

of the falling ice crystal with the relationship among the Reynolds number,

the Best number and the axial ratio. Finally, a set of simplified parameterized

equations has been generated that is experimentally consistent and suitable

for cloud modeling and analysis.

The empirical equations generated in this thesis based on the specific

functional style of the theory have the advantage over the best fit polynomial

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