Spectrometric measurements of atmospheric propane (C 3 H 8 )

Abstract. We report measurements of atmospheric C3H8 from analysis of ground-based, solar absorption spectra from the JPL MkIV interferometer. Using the strong Q-branch absorption feature at 2967 cm−1, we can measure C3H8 in locations where its abundance is enhanced by proximity to sources (e.g., large natural gas fields, mega-cities). A case study of MkIV C3H8 measurements from Ft. Sumner, New Mexico, show large variations that are strongly correlated with ethane (C2H6) amounts and with back-trajectories from SE New Mexico and West 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 MKIV solar occultation measurements from balloon, C3H8 was not detected at any altitude in any flight.