Observationally Constrained NOx-Catalyzed Ozone Production in the Upper Troposphere During the Asian Summer Monsoon
Year: 2025
Authors: Waxman EM., Gao R.S., Thornberry T., McLaughlin R., Novak G., Atlas E., Schauffler S., Treadaway V., Smith K., Lueb R., Hendershot R., Campos T., Wolfe G., St Clair JM., Delaria E., Anderson D., Viciani S., D’Amato F., Bianchini G., Barucci M., Gurganus C., Iraci L., Podolske J., Diskin G., Choi Y., DiGangi J., Bui TP., Dean-Day J., Gatebe C., Pan L.L., Rollins A.
Autors Affiliation: Univ Colorado Boulder, CIRES, Boulder, CO 80309 USA; NOAA, Chem Sci Lab, Boulder, CO 80305 USA; Univ Miami, Rosenstiel Sch Marine Atmospher & Earth Sci, Dept Atmospher Sci, Miami, FL 33136 USA; NSF Natl Ctr Atmospher Res, Atmospher Chem Observat & Modeling Lab, Boulder, CO USA; NASA, Ames Res Ctr, Moffett Field, CA USA; NASA, Goddard Space Flight Ctr, Greenbelt, MD USA; Univ Maryland Baltimore Cty, Baltimore, MD USA; CNR, Natl Inst Opt CNR INO, Sesto Fiorentino, Italy; NASA, Langley Res Ctr, Hampton, VA USA; Bay Area Environm Res Inst, Moffett Field, CA USA.
Abstract: Intense and frequent convection occurring during the Asian Summer Monsoon (ASM) rapidly transports surface emissions to the upper troposphere (UT). Depending on their chemical reactivities, pollutants transported to the UT via this mechanism may either undergo chemistry in the UT region or be transported into the lower stratosphere. The Asian Summer Monsoon Chemical and CLimate Impact Project (ACCLIP) used high-altitude research aircraft to characterize chemistry in the tropopause region within the ASM anticyclone and outflows of monsoon convection during summer 2022. Here, we use measurements of trace gases from ACCLIP and results from a 0-D model constrained by airborne observations to calculate net ozone production rates in airmasses influenced by recent convection and in the summer monsoon background upper troposphere/lower stratospheric air. We find that ozone production inside the polluted air downstream of recent convection is up to one order of magnitude higher than that in the cleaner background upper troposphere. The ozone production is driven by NO + HO2 produced from CO and OVOC oxidation, rather than from organic peroxy radicals produced from volatile organic compounds inside the highly polluted airmasses. Consistent with previous modeling work, we find efficient HOx (OH + HO2) cycling is dominated by reactions with CO. Ozone production in this region is primarily NOx-limited and increases with higher NOx such as during convective events with lightning NOx production. Further, we find that the dominant impact of enhanced NOx here is through acceleration of HOx cycling, and thus an increase in ozone production.
Journal/Review: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
Volume: 130 (19) Pages from: e2024JD043218-1 to: e2024JD043218-2
More Information: The ACCLIP campaign was funded by the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA). NOAA authors were supported by the NOAA Earth’s Research Budget program and NASA UACO Grant NNH20ZDA001N-UACO. This research was supported in part by NOAA cooperative agreement NA22OAR4320151. EA and the WAS team acknowledge support from NASA Grant 80NSSC22K1284 and NSF-AGS Grant 1853948. NCAR authors were supported by the NSF National Center for Atmospheric Research, sponsored by the U.S. National Science Foundation under Cooperative Agreement No. 1852977. NASA GSFC authors were supported by the NASA Upper Atmospheric Research Program. ERD was supported under the NASA Postdoctoral Program. The COLD2 deployment was funded by the European Space Agency (ESA) contract QA4EO- ACCLIP. The COMA team was supported by the NASA Earth Science Research and Analysis Program (K. Jucks, J. Kaye), the NASA Postdoctoral Program, and NASA Ames Internal Research and Development funding. The DLH team was funded directly by the NASA Upper Atmosphere Program. The authors acknowledge E. Apel and R. Hornbrook for the TOGA-ToF data collected on the NCAR GV aircraft and S. Ciciora for invaluable electronics support. They also acknowledge the WB-57 and GV pilots, engineers, technicians, and ground crews and support from Osan Air Base.KeyWords: ozone; Asian Summer MonsoonDOI: 10.1029/2024JD043218
