DISSERTATION DEFENSE
"Molecular Spectroscopy of Atmospheres in the Infrared"
Dylan English
Old Dominion University
OCNPS 304 Physics Conference Room
Wednesday, October 28, 2026
2:00 pm
Abstract:
Remote measurements of atmospheres are made possible through molecular spectroscopy. Discovery of dynamics, chemistry, and other phenomena requires a methodology of observation that defines the constituents of these atmospheres and their interactions. Modeling of the Earth's atmosphere requires global information only possible through remote sensing. Measurements by the Atmospheric Chemistry Experiment (ACE) satellite record spectra in solar occultation. Using this data, absorption of CO2 isotopologues derives volume mixing ratios throughout the layers of the atmosphere. The role of photolysis in the upper atmosphere for 17 OCO and 18OCO fractionation has been analyzed and found to be "mass independent." A new data product from the (ACE) satellite provides approximately 22 years of near-global coverage of stratospheric sulfate aerosol (SSA). Direct coincidence and general overview comparisons are made between in-situ measurements from balloon and aircraft missions, and remote sensing measurements from ACE. Bimodal versus monomodal log-normal distributions between the different measuring techniques show good agreement, with an effective radius percent difference less than 10% above 20 km. Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) measurements of SSA size distribution agree with the shape of ACE's effective radius but sustain a 25% positive shift throughout. In the lab, a Fourier transform spectrometer is used to make measurements of the symmetric stretch vibrational band of ammonia. The first measurements of high-temperature hydrogen broadening of the ro-vibrational lines are reported for 71 lines in the P and R branches.