Deep Convective Trace Gas Transport to the UTLS: Highlighting Remote Sensing and Modeling Challenges With ACCLIP Campaign In Situ CO Observations
Year: 2026
Authors: Gurganus C., Rollins A., Waxman E., Pan LL., Smith WP., Tilmes S., Chin M., Bian HS., Viciani S., D’Amato F., Bianchini G., Barucci M., Campos T., Ullmann K., Iraci LT., Podolske JR., Davis S., Baier BC., Barret B., Le Flochmoln E., Clerbaux C., Boynard A., DeLone S., Bednarz E., Schwarz JP., Thornberry TD.
Autors Affiliation: Univ Colorado, Cooperat Inst Res Environm Sci CIRES, Boulder, CO 80309 USA; NOAA Chem Sci Lab CSL, Boulder, CO 80305 USA; NSF Natl Ctr Atmospher Res NCAR, Atmospher Chem Observat & Modeling ACOM Lab, Boulder, CO USA; Univ Maryland, Goddard Earth Sci Technol & Res GESTAR II 2, Baltimore, MD USA; NASA Goddard Space Flight Ctr, Chem & Dynam Branch, Greenbelt, MD USA; CNR, Natl Inst Opt CNR INO, Sesto Fiorentino, Italy; NASA, Atmospher Sci Branch, Ames Res Ctr, Moffett Field, CA USA; NOAA, Global Monitoring Lab GML, Boulder, CO USA; Univ Toulouse III Paul Sabatier, LAERO, CNRS, Toulouse, France; Sorbonne Univ, LATMOS, IPSL, UVSQ,CNRS, Paris, France.
Abstract: China is a major source of anthropogenic emissions, with important implications for chemical composition and aerosol processes in the upper troposphere and lower stratosphere (UTLS), particularly within the Asian Summer Monsoon (ASM) anticyclone. Carbon monoxide (CO) is a robust tracer of anthropogenic influence and is routinely observed by remote platforms. In the ASM region, the GEOS-FP forecast system predicts frequent, rapid convective transport of boundary-layer CO into the UTLS. During the 2022 Asian Summer Monsoon Chemical and Climate Impact Project (ACCLIP), five in-situ spectrometers aboard two coordinated research aircraft provided some of the first vertically resolved UTLS CO measurements in the ASM region, providing generally good agreement with forecast abundances. On 19 August 2022, exceptionally enhanced UTLS CO, exceeding 325 ppb, was recorded by both ACCLIP research aircraft over the Yellow Sea west of Korea, exceeding GEOS-FP predictions and producing a pronounced C-shaped vertical profile indicative of strong convective outflow. None of the satellite profile products examined (MLS, MOPITT, AIRS, CrIS, or IASI) captured the magnitude or vertical structure of this enhancement, highlighting limitations in remote-sensing sensitivity to sharp UTLS gradients. Simulations from global models with sophisticated chemistry schemes, GEOS-GOCART and CESM2-WACCM, attribute the sampled plume to a local convective outbreak approximately 12 hr before in-situ sampling. GEOS-GOCART better reproduced the observed profile, while CESM2-WACCM simulated weaker lofting; however, both underestimated the magnitude of CO in the UTLS. This case underscores challenges in validating localized deep-convective transport and demonstrates the continued need for high-resolution (spatial and temporal) in-situ UTLS observations.
Journal/Review: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
Volume: 131 (13) Pages from: e2025JD045541-1 to: e2025JD045541-2
More Information: The ACCLIP campaign was supported by the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and the Office of Naval Research (ONR). We gratefully acknowledge the invaluable contributions of Steve Ciciora and Ru-Shan Gao in the design and deployment of the ACOS spectrometer. The COLD2 deployment was funded by the European Space Agency (ESA) under contract QA4EO486 ACCLIP. The NSF NCAR Gulfstream-V (GV) was managed and operated by the NSF NCAR Earth Observing Laboratory, with support from the U.S. National Science Foundation under Cooperative Agreement 1852977. The NCAR FTS observation programs in Boulder, CO were supported under contract by NASA. The NDACC data used in this study were provided by Isao Murata (Tsukuba, Japan) and James Hannigan (Boulder, CO). The authors also acknowledge the AERIS data infrastructure (https://www.aeris-data.fr) for providing access to IASI CO data. We also thank Tim Newberger, Sonja Wolter, and Jack Higgs for their assistance with NOAA AirCore flights. This research was supported by the NOAA Cooperative Agreement NA22OAR4320151 for the Cooperative Institute for Earth System Research and Data Science (CIESRDS) and by the NOAA Earth’s Radiation Budget Initiative (03-01-07-001). The statements, findings, conclusions, and recommendations are those of the authors and do not necessarily reflect the views of NOAA or the U.S. Department of Commerce. NOAA and CIRES authors were supported in part by the National Aeronautics and Space Administration (NASA) through the Upper Atmosphere Composition Observations (UACO) program under Grant NNH20ZDA001N-UACO. This support contributed to the development, operation, and analysis of airborne and in situ atmospheric composition measurements, as well as associated modeling and data interpretation activities carried out as part of this study.KeyWords: Asian summer monsoon; carbon monoxide; remote sensing; deep convection; airborne field campaign; upper troposphere and lower stratosphereDOI: 10.1029/2025JD045541
