TY - JOUR
T1 - Arctic tropospheric ozone
T2 - Assessment of current knowledge and model performance
AU - Whaley, Cynthia H.
AU - Law, Kathy S.
AU - Hjorth, Jens Liengaard
AU - Skov, Henrik
AU - Arnold, Stephen R.
AU - Langner, Joakim
AU - Pernov, Jakob Boyd
AU - Bergeron, Garance
AU - Bourgeois, Ilann
AU - Christensen, Jesper H.
AU - Chien, Rong You
AU - Deushi, Makoto
AU - Dong, Xinyi
AU - Effertz, Peter
AU - Faluvegi, Gregory
AU - Flanner, Mark
AU - Fu, Joshua S.
AU - Gauss, Michael
AU - Huey, Greg
AU - Im, Ulas
AU - Kivi, Rigel
AU - Marelle, Louis
AU - Onishi, Tatsuo
AU - Oshima, Naga
AU - Petropavlovskikh, Irina
AU - Peischl, Jeff
AU - Plummer, David A.
AU - Pozzoli, Luca
AU - Raut, Jean Christophe
AU - Ryerson, Tom
AU - Skeie, Ragnhild
AU - Solberg, Sverre
AU - Thomas, Manu A.
AU - Thompson, Chelsea
AU - Tsigaridis, Kostas
AU - Tsyro, Svetlana
AU - Turnock, Steven T.
AU - Von Salzen, Knut
AU - Tarasick, David W.
N1 - Publisher Copyright:
© 2023 Cynthia H. Whaley et al.
PY - 2023
Y1 - 2023
N2 - As the third most important greenhouse gas (GHG) after carbon dioxide (CO2) and methane (CH4), tropospheric ozone (O3) is also an air pollutant causing damage to human health and ecosystems. This study brings together recent research on observations and modeling of tropospheric O3 in the Arctic, a rapidly warming and sensitive environment. At different locations in the Arctic, the observed surface O3 seasonal cycles are quite different. Coastal Arctic locations, for example, have a minimum in the springtime due to O3 depletion events resulting from surface bromine chemistry. In contrast, other Arctic locations have a maximum in the spring. The 12 state-of-the-art models used in this study lack the surface halogen chemistry needed to simulate coastal Arctic surface O3 depletion in the springtime; however, the multi-model median (MMM) has accurate seasonal cycles at non-coastal Arctic locations. There is a large amount of variability among models, which has been previously reported, and we show that there continues to be no convergence among models or improved accuracy in simulating tropospheric O3 and its precursor species. The MMM underestimates Arctic surface O3 by 5 % to 15 % depending on the location. The vertical distribution of tropospheric O3 is studied from recent ozonesonde measurements and the models. The models are highly variable, simulating free-tropospheric O3 within a range of ±50 % depending on the model and the altitude. The MMM performs best, within ±8 % for most locations and seasons. However, nearly all models overestimate O3 near the tropopause (-1/4300 hPa or -1/48 km), likely due to ongoing issues with underestimating the altitude of the tropopause and excessive downward transport of stratospheric O3 at high latitudes. For example, the MMM is biased high by about 20 % at Eureka. Observed and simulated O3 precursors (CO, NOx, and reservoir PAN) are evaluated throughout the troposphere. Models underestimate wintertime CO everywhere, likely due to a combination of underestimating CO emissions and possibly overestimating OH. Throughout the vertical profile (compared to aircraft measurements), the MMM underestimates both CO and NOx but overestimates PAN. Perhaps as a result of competing deficiencies, the MMM O3 matches the observed O3 reasonably well. Our findings suggest that despite model updates over the last decade, model results are as highly variable as ever and have not increased in accuracy for representing Arctic tropospheric O3.
AB - As the third most important greenhouse gas (GHG) after carbon dioxide (CO2) and methane (CH4), tropospheric ozone (O3) is also an air pollutant causing damage to human health and ecosystems. This study brings together recent research on observations and modeling of tropospheric O3 in the Arctic, a rapidly warming and sensitive environment. At different locations in the Arctic, the observed surface O3 seasonal cycles are quite different. Coastal Arctic locations, for example, have a minimum in the springtime due to O3 depletion events resulting from surface bromine chemistry. In contrast, other Arctic locations have a maximum in the spring. The 12 state-of-the-art models used in this study lack the surface halogen chemistry needed to simulate coastal Arctic surface O3 depletion in the springtime; however, the multi-model median (MMM) has accurate seasonal cycles at non-coastal Arctic locations. There is a large amount of variability among models, which has been previously reported, and we show that there continues to be no convergence among models or improved accuracy in simulating tropospheric O3 and its precursor species. The MMM underestimates Arctic surface O3 by 5 % to 15 % depending on the location. The vertical distribution of tropospheric O3 is studied from recent ozonesonde measurements and the models. The models are highly variable, simulating free-tropospheric O3 within a range of ±50 % depending on the model and the altitude. The MMM performs best, within ±8 % for most locations and seasons. However, nearly all models overestimate O3 near the tropopause (-1/4300 hPa or -1/48 km), likely due to ongoing issues with underestimating the altitude of the tropopause and excessive downward transport of stratospheric O3 at high latitudes. For example, the MMM is biased high by about 20 % at Eureka. Observed and simulated O3 precursors (CO, NOx, and reservoir PAN) are evaluated throughout the troposphere. Models underestimate wintertime CO everywhere, likely due to a combination of underestimating CO emissions and possibly overestimating OH. Throughout the vertical profile (compared to aircraft measurements), the MMM underestimates both CO and NOx but overestimates PAN. Perhaps as a result of competing deficiencies, the MMM O3 matches the observed O3 reasonably well. Our findings suggest that despite model updates over the last decade, model results are as highly variable as ever and have not increased in accuracy for representing Arctic tropospheric O3.
UR - http://www.scopus.com/inward/record.url?scp=85147316661&partnerID=8YFLogxK
U2 - 10.5194/acp-23-637-2023
DO - 10.5194/acp-23-637-2023
M3 - Journal article
AN - SCOPUS:85147316661
SN - 1680-7316
VL - 23
SP - 637
EP - 661
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 1
ER -