Spectrometric measurements of atmospheric propane (C3H8)

Abstract

We report measurements of atmospheric C3H8 from analysis of ground-based solar absorption spectra from the Jet Propulsion Laboratory (JPL) MkIV interferometer. Using the strong Q-branch absorption feature at 2967cm-1, we can measure C3H8 in locations where its abundance is enhanced by proximity to sources (e.g., large natural gas fields, megacities). A case study of MkIV C3H8 measurements from Fort Sumner, New Mexico, shows that amounts are strongly correlated with ethane (C2H6) and with back-trajectories from SE New Mexico and western Texas, where the Permian Basin oil and natural gas field is located. Measurements from JPL, California, also show large C3H8 enhancements on certain days but more correlated with CO than C2H6. From high-altitude balloon-borne MkIV solar occultation measurements, C3H8 was not detected at any altitude (5-40km) in any of the 25 flights.