Deep Convective Trace Gas Transport to the UTLS: Highlighting Remote Sensing and Modeling Challenges With ACCLIP Campaign In Situ CO Observations

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.

Authors

Institutions

Publication Details

Journal
Journal of Geophysical Research Atmospheres
Published
2026-07-01
DOI
https://doi.org/10.1029/2025jd045541
Primary Topic
Atmospheric Ozone and Climate
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Deep Convective Trace Gas Transport to the UTLS: Highlighting Remote Sensing and Modeling Challenges With ACCLIP Campaign In Situ CO Observations

É. Le Flochmoën, Silvia Viciani, Colin Gurganus, Sean M. Davis et al.
Journal of Geophysical Research Atmospheres
Atmospheric Ozone and Climate
article

Deep Convective Trace Gas Transport to the UTLS: Highlighting Remote Sensing and Modeling Challenges With ACCLIP Campaign In Situ CO Observations

É. Le Flochmoën, Silvia Viciani, Colin Gurganus, Sean M. Davis, Huisheng Bian, M. Barucci, Laura L. Pan, Laura T. Iraci, Simone Tilmes, Bianca C. Baier, Ewa Bednarz, Mian Chin, Anne Boynard, Joshua Peter Schwarz, Warren P. Smith, Cathy Clerbaux, Giovanni Bianchini, Andrew W. Rollins, Troy Thornberry, James R. Podolske, Francesco D’Amato, Kirk Ullmann, Eleanor M. Waxman, Samantha DeLone, Teresa Campos, Brice Barret
article en

Abstract

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 of Geophysical Research AtmospheresVol. 131(13)
NSF National Center for Atmospheric Research (US), University of Maryland, Baltimore (US), Ames Research Center (US), Centre National de la Recherche Scientifique (FR), Goddard Space Flight Center (US), Université Toulouse III - Paul Sabatier (FR), Cooperative Institute for Research in Environmental Sciences (US), University of Colorado Boulder (US), Université de Versailles Saint-Quentin-en-Yvelines (FR), Sorbonne Université (FR), Institut Pierre-Simon Laplace (FR), NOAA Chemical Sciences Laboratory (US), Laboratoire atmosphères, milieux, observations spatiales (FR), National Research Council (IT), University of Maryland, Baltimore County (US)
European Space Agency
Climate action
Openalex Percentile: Top 8%
Atmospheric Ozone and Climate
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.