Date of Award

January 2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Atmospheric Sciences

First Advisor

David J. Delene

Abstract

The tremendous safety and monetary impacts of long-duration fog events continue to spur interest in its anthropogenic dissipation. With the emergence of the Unmanned Aircraft Systems (UAS) platform and the development of miniaturized atmospheric sensors, more efficient methods of fog research and anthropogenic fog dispersal may be achieved. The feasibility of a supercooled fog dispersal project in the Red River Valley and the efficacy of using the UAS platform to acquire in-situ fog microphysical data are explored. A 30-year climatology of the Red River Valley indicates increased supercooled fog potential between early November through early April, peaking in March. Five UAS missions conducted during March of 2023 demonstrate in-situ, boundary layer measurements in both high- and low-visibility conditions. The IMet-XQ2 (temperature, humidity, and location) and MiniOFS (visibility) instruments deployed on the UAS platform compare well to surface counterparts and performed sufficiently for proper representation of the atmosphere; however, aspiration of the sensors is essential for accurate measurements. The MiniOFS overestimates low-visibility events whereas the IMet-XQ2 relative humidity sensor underestimates moist atmospheres. Vertical profiling of two fog events successfully resolved the fog layers and determined fog-top heights of 114 m (375 ft) and 92 m (300 ft) AGL. During the last mission, a strong temperature inversion is present at the fog layer top. The UAS platform is deemed sufficient for in-situ data acquisition within the boundary layer, whereas a low average of 14 hours of supercooled fog per year indicate a need for additional cost effectiveness assessments for Red River Valley fog abatement feasibility.

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