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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The value of these data can be seen in Fig. 1 where the mass of the

crystal, grown in the cloud tunnel for 10 minutes, was compared with that

calculated by Jayaweera (1971) and Miller and Young (1979). The large

discrepancy between these data and the results of the numerical calculations

illustrates the space for model improvement. Indeed, most of these models

are based on previous theories and these experimental data can serve to

improve the theories.

Thus, an opportunity is present to improve the theoretical basis in ice

phase cloud microphysics in comparison with the unique supercooled cloud

tunnel data of ice crystal growth, and the purpose of this thesis is to make use

of it. This work will set out to accomplish at least three tasks. First, some

results of microphysical theory will be verified with experimental data.

Second, time - dependent equations of mass, a- and c-axial lengths, and fall

velocity applicable to different regimes of growth will be developed by using

theories and measured data. Finally, a set of simplified parameterized

equations will be generated that will be experimentally and theoretically

consistent and suitable for cloud modeling.

To accomplish this task, the thesis is divided into six chapters. Chapter 2

will discuss the experimental data to be used in this thesis. Chapter 3 is

designated for development of the time dependent equations for ice crystal

growth parameters. An equation describing the fall behavior of a crystal based

upon the Reynolds number and habit will be discussed in Chapter 4. A set of

simplified parameterized equations applicable for cloud modeling will be

derived in Chapter 5. The final chapter will be devoted to summarizing

results and drawing conclusions.

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