WMOD00406

• Contract/Permit #: 7-07-83-V0001
• Title: Turbulant Diffusion Studies of Winter Storms Over the Sierra Nevada Mountains
• Date: 12/1/1981
• Weather Modification - Doc Type: Report

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Karacostas, Theodore S., TUrbulent dlrtu~ionstudies or winter storms
over the Sierra N~vada MOuntains, Ph. D.,
Department of Atmospheric Science, University
of Wyoming, December, 1981.

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The Lagrangian Turbulent Diffusion (LTD) model is developed, criti-

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cally evaluated and applied over the Sierra Nevada Mountains. The data

were co llec ted in the course 0 f the Bureau 0 f Rec lama t ion's Sierra Coope-

rative Pilot ProJect (SCPP) in the field seasons 1977-78, 1978-79, and

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1979-80.

The statistical theory was used as the basic theoretical framework

for the development of the model, which expresses the complex process of

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turbulent diffusion as an analytical equation. The LTD model describes

the time his tory' 0 f the seeding ma ter ia I as they wander through the flow

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field, and g:ives a fundamentally correct picture of the actual mechanism

of turbulent d iffus ion.

It is shown theoretically and experimentally

that the LTD' model is an appropriate method to predict the diffusion of

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a seeded plume for diffusion times longer than the characteristic time

associated with the most energetic eddies.

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The important assumptions and hypotheses used in the development of

the LTD model are validated theoretically and experimentally. Procedures

for adopting aircraft measurements to the LTD model are developed and the-

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oretically evaluated. The Taylor's frozen-turbulence hypothesis is shown

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