Assessment of regional and interannual variations in tropospheric ozone in chemical reanalyses
11 affiliations
- 1University of Toronto (Toronto, Canada)
- 2Department of Physics, University of Toronto, Toronto, Ontario, Canada
- 3Department of Marine Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27607, USA
- 4NSF National Center for Atmospheric Research, Boulder, CO, USA
- 5Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA, USA
- 6Japan Agency for Marine-Earth Science and Technology, Yokohama 2360001, Japan
- 7European Centre for Medium-range Weather Forecasts (ECMWF), Reading, UK
- 8College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- 9LAPC & ICCES, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
- 10Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, the Netherlands
- 11Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
Abstract
We evaluate regional and interannual variations in tropospheric ozone in five chemical reanalyses, consisting of the Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA), the second-generation Tropospheric Chemistry Reanalysis (TCR-2), the GEOS-Chem reanalysis, the Community Multiscale Air Quality (CMAQ) regional analysis, and the Chinese air quality reanalysis (CAQRA). We find that there are large regional differences (about 10–15 nmol mol-1) in mean surface ozone between the reanalyses. GEOS-Chem has high ozone relative to the ensemble mean across most continental regions, whereas CAMSRA has low ozone. Comparison with surface ozone observations shows that the reanalyses are biased high relative to the observations, with surface ozone biases exceeding 10 nmol mol-1 in GEOS-Chem. We find that CAMSRA has the smallest bias with respect to the observations, with negative biases in Europe, and in the central and western US, and positive biases everywhere else. In the free troposphere the reanalyses are in good agreement, and the mean bias between the reanalyses and ozonesonde observations are small, less than 4 nmol mol-1 at 500 hPa. In addition, the correlations between the ozonesondes and the reanalyses are as high as 0.8 and 0.9 in the southern and northern midlatitudes respectively. The results suggest that chemical reanalyses should provide valuable information for quantifying variations in ozone in the free troposphere. However, to enhance the utility of the surface ozone analyses, improvements in the reanalyses are needed to better exploit assimilated observations to mitigate the impact of discrepancies in the model chemistry and ozone precursor emissions.
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BibTeX
@article{jones2026assessment,
title = {{Assessment of regional and interannual variations in tropospheric ozone in chemical reanalyses}},
author = {Dylan B. A. Jones and Lucas Prates and Zhen Qu and William Y. Y. Cheng and Kazuyuki Miyazaki and Takashi Sekiya and Antje Inness and Rajesh Kumar and Xiao Tang and H. M. Worden and Gerbrand Koren and Vincent Huijnen},
journal = {Atmospheric chemistry and physics},
year = {2026},
month = may,
doi = {10.5194/acp-26-6655-2026},
url = {https://doi.org/10.5194/acp-26-6655-2026},
note = {CC BY},
}
RIS
TY - JOUR
TI - Assessment of regional and interannual variations in tropospheric ozone in chemical reanalyses
AU - Dylan B. A. Jones
AU - Lucas Prates
AU - Zhen Qu
AU - William Y. Y. Cheng
AU - Kazuyuki Miyazaki
AU - Takashi Sekiya
AU - Antje Inness
AU - Rajesh Kumar
AU - Xiao Tang
AU - H. M. Worden
AU - Gerbrand Koren
AU - Vincent Huijnen
PY - 2026
DA - 2026/05/18
JO - Atmospheric chemistry and physics
DO - 10.5194/acp-26-6655-2026
UR - https://doi.org/10.5194/acp-26-6655-2026
AB - We evaluate regional and interannual variations in tropospheric ozone in five chemical reanalyses, consisting of the Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA), the second-generation Tropospheric Chemistry Reanalysis (TCR-2), the GEOS-Chem reanalysis, the Community Multiscale Air Quality (CMAQ) regional analysis, and the Chinese air quality reanalysis (CAQRA). We find that there are large regional differences (about 10–15 nmol mol-1) in mean surface ozone between the reanalyses. GEOS-Chem has high ozone relative to the ensemble mean across most continental regions, whereas CAMSRA has low ozone. Comparison with surface ozone observations shows that the reanalyses are biased high relative to the observations, with surface ozone biases exceeding 10 nmol mol-1 in GEOS-Chem. We find that CAMSRA has the smallest bias with respect to the observations, with negative biases in Europe, and in the central and western US, and positive biases everywhere else. In the free troposphere the reanalyses are in good agreement, and the mean bias between the reanalyses and ozonesonde observations are small, less than 4 nmol mol-1 at 500 hPa. In addition, the correlations between the ozonesondes and the reanalyses are as high as 0.8 and 0.9 in the southern and northern midlatitudes respectively. The results suggest that chemical reanalyses should provide valuable information for quantifying variations in ozone in the free troposphere. However, to enhance the utility of the surface ozone analyses, improvements in the reanalyses are needed to better exploit assimilated observations to mitigate the impact of discrepancies in the model chemistry and ozone precursor emissions.
SN - 1680-7316
SN - 1680-7324
ER -