<b>Observing Lake Michigan Evaporation Influence on Atmospheric Moisture Using Airborne Measurements of Stable Isotopologues in Water Vapor</b>

<p dir="ltr">The Great Lakes region offers opportunities for shipping and recreation and provides water for consumption to large parts of the United States and Canada. The Lakes themselves significantly influence the downwind states' and provinces' regional weather and climate. Seasonal storms and weather conditions driven by the Great Lakes are challenging to model due to simplifications of the processes involved in evaporation and atmospheric boundary conditions, such as transport, turbulence, and mixing. These processes are also difficult to measure directly, resulting in a lack of ground-truth data for validating models. Additional tracers of evaporation from the lake's surface and resulting boundary layer transport could enhance the understanding of these processes, and stable water vapor isotope tracers could fill that gap.</p><p dir="ltr">In this thesis, I tested commonly used tubing types to determine if there was a superior material for atmospheric stable water vapor isotope analysis. All of the commonly used materials performed similarly. I also utilized Purdue’s Airborne Laboratory for Atmospheric Research (ALAR) to observe stable water vapor isotopes on a broad atmospheric scale. The lowest hundreds of meters of the atmospheric boundary layer above Lake Michigan showed an increase in water vapor mole fractions and shifts in the isotopic content from the flight observations, indicative of a lake internal boundary layer and lake evaporation.</p>