Publication Date

Summer 2018

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology

Advisor

Craig B. Clements

Keywords

fire, instrumentation, micrometeorology, terrain, turbulence, vorticity

Subject Areas

Meteorology; Atmospheric sciences; Remote sensing

Abstract

An experiment was designed to capture micrometeorological observations

during a fire spread on a simple slope. Three towers equipped with a variety of

instrumentation, an array of fire-sensing packages, and a Doppler lidar was

deployed to measure various aspects of the fire. Pressure and temperature

perturbations were analyzed for each of the grid packages to determine if the fire

intensity could be observed in the covariance of the two variables. While two of

the packages measured a covariance less than -15 °C hPa, there was no clear

trend across the grid. The fire front passage at each of the three towers on the

slope yielded extreme swings in observed turbulent kinetic energy and sensible

heat flux. Vertical velocity turbulence spectra showed that the high-intensity fire

front passage at the bottom tower was 2 to 3 orders of magnitude larger than the

low-intensity fire front passages at the top two towers. Opposing wind regimes on

the slope caused a unique L-shaped pattern to form in the fire front. A vorticity

estimation from the sonic anemometers showed that vorticity reached a

maximum just as a fire whirl formed in the bend of the L-shaped fire front, leading

to a rapid increase in fire spread.

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