Global O&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;–CO correlations in a chemistry and transport model during July–August: evaluation with TES satellite observations and sensitivity to input meteorological data and emissions

Choi, Hyun-Deok; Liu, Hongyu; Considine, David B.; Allen, D. J.; Duncan, B. N.; Horowitz, Larry W.; Rodríguez, José M.; Strahan, S. E.; Zhang, Lin; Liu, Xiong; Damon, Megan; Steenrod, Stephen D.

doi:10.5194/acp-17-8429-2017

Cited by 11 publications

(9 citation statements)

References 75 publications

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“…Ozonesonde data showed that Summit frequently encountered high O 3 and low water vapor events (e.g., 9-11 July 2008), which were likely of upper tropospheric or stratospheric origin , but these were not captured by the model, which implied that GEOS-Chem possibly underestimated STE for O 3 over Summit. This is consistent with the study by Choi et al (2017), which found low bias with model-simulated O 3 mixing ratios for the upper troposphere of the high-latitude Northern Hemisphere compared with ozonesonde data and attributed the low bias to an underestimated STE in the model.…”

Section: Osupporting

confidence: 92%

Surface ozone and its precursors at Summit, Greenland: comparison between observations and model simulations

Huang¹,

Wu²,

Kramer³

et al. 2017

Atmos. Chem. Phys.

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Abstract. Recent studies have shown significant challenges for atmospheric models to simulate tropospheric ozone (O 3 ) and its precursors in the Arctic. In this study, ground-based data were combined with a global 3-D chemical transport model (GEOS-Chem) to examine the abundance and seasonal variations of O 3 and its precursors at Summit, Greenland (72.34 • N, 38.29 • W; 3212 m a.s.l.). Model simulations for atmospheric nitrogen oxides (NO x ), peroxyacetyl nitrate (PAN), ethane (C 2 H 6 ), propane (C 3 H 8 ), carbon monoxide (CO), and O 3 for the period July 2008-June 2010 were compared with observations. The model performed well in simulating certain species (such as CO and C 3 H 8 ), but some significant discrepancies were identified for other species and further investigated. The model generally underestimated NO x and PAN (by ∼ 50 and 30 %, respectively) for MarchJune. Likely contributing factors to the low bias include missing NO x and PAN emissions from snowpack chemistry in the model. At the same time, the model overestimated NO x mixing ratios by more than a factor of 2 in wintertime, with episodic NO x mixing ratios up to 15 times higher than the typical NO x levels at Summit. Further investigation showed that these simulated episodic NO x spikes were always associated with transport events from Europe, but the exact cause remained unclear. The model systematically overestimated C 2 H 6 mixing ratios by approximately 20 % relative to observations. This discrepancy can be resolved by decreasing anthropogenic C 2 H 6 emissions over Asia and the US by ∼ 20 %, from 5.4 to 4.4 Tg year −1 . GEOS-Chem was able to reproduce the seasonal variability of O 3 and its spring maximum. However, compared with observations, it underestimated surface O 3 by approximately 13 % (6.5 ppbv) from April to July. This low bias appeared to be driven by several factors including missing snowpack emissions of NO x and nitrous acid in the model, the weak simulated stratosphereto-troposphere exchange flux of O 3 over the summit, and the coarse model resolution.

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Section: Osupporting

confidence: 92%

Surface ozone and its precursors at Summit, Greenland: comparison between observations and model simulations

Huang¹,

Wu²,

Kramer³

et al. 2017

Atmos. Chem. Phys.

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“…Although cloud correction experiments suggest that these biases in cloud fields account for most of the bias in the simulated relationship between sulfate and SPEI under M2GC, correcting these biases does little to reduce the positive bias in sulfate concentrations. Our results emphasize the critical role of meteorological inputs in simulating sulfate, and provide a new perspective on a theme discussed by previous studies (Choi et al, 2017;Gong et al, 2006;Liu et al, 2009;Luo et al, 2011;Mueller et al, 2006;von Salzen et al, 2000;Yu et al, 2017;J. Zhang et al, 2007).…”

Section: 1029/2018jd029693supporting

confidence: 80%

Evaluating the Response of Summertime Surface Sulfate to Hydroclimate Variations in the Continental United States: Role of Meteorological Inputs in the GEOS‐Chem Model

et al. 2019

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Understanding the response of sulfate to climate change is crucial given tight couplings between sulfate and the hydrological cycle. As the sources and sinks of sulfate are sensitive to cloud and precipitation processes, the accuracy of model simulations depends on the accuracy of these meteorological inputs. In this study, we evaluate the GEOS‐Chem model in simulating summertime surface sulfate concentrations in the continental United States across different levels of dryness and compare the model performance based on two sets of meteorological fields: Modern Era Retrospective Analysis for Research and Applications (MERRA) and MERRA‐2. Both simulations fail to reproduce observed increases in sulfate during drought, as indicated by negative correlation slopes between surface sulfate concentrations and the standardized precipitation evapotranspiration index (SPEI). This deficiency can be largely attributed to too large a decrease in clouds and hence aqueous phase sulfate production as conditions shift from wet to dry. MERRA‐2‐driven GEOS‐Chem (M2GC) shows improvements in cloud and precipitation fields relative to the MERRA‐driven GEOS‐Chem, hence eliminating approximately half of the bias in the simulated sulfate‐SPEI slope. However, M2GC still underestimates boundary layer cloud fraction, overestimates liquid water content, and overestimates the rates of the decrease in both quantities as conditions become drier. Explicitly correcting these cloud biases in M2GC results in a 60–80% reduction of the bias in the simulated sulfate‐SPEI slope. The strong sensitivity of simulated sulfate to prescribed cloud fields suggests the need for more comprehensive assessment of cloud inputs for sulfate simulations under current and future climate change scenarios.

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“…e conclusion based on remote sensing data in this study is very macroscopic, and some details require further separate research. In addition, specific vertical distribution, convection processes, longrange transport, and chemical nonlinear processes require an atmospheric chemical transport model for sensitivity experiments to quantify its effects [59].…”

Section: Discussionmentioning

confidence: 99%

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Li-hua

Zhang

Zheng

et al. 2019

Advances in Meteorology

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Compared with other regions in China, air pollution on the North China Plain (NCP) is serious. Fine particle pollution has been studied in-depth, but there is less research on long-term troposphere ozone (O 3 ) variation. is study focuses on the summer interannual tropospheric O 3 variation on the NCP and its influential factors. Our analysis relies on satellite observations (O 3 , nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), carbon monoxide (CO), and formaldehyde (HCHO), determined as vertical column density of the troposphere) and dynamical processes (El Niño-Southern Oscillation (ENSO), potential vorticity (PV), the quasibiennial oscillation (QBO), and East Asian summer monsoon index (EASMI)). Our results show the vertical column density of tropospheric O 3 has a transition from the increasing trend to decreasing trend during the summer of 2005-2016. e summer series of tropospheric O 3 show two distinct phases: the first phase (2005)(2006)(2007)(2008)(2009)(2010)(2011), with an average growth rate of 0.55 ± 0.20 DU/yr, and a second phase (2012)(2013)(2014)(2015)(2016), with an average reduction rate of 0.16 ± 0.23 DU/yr. e tropospheric NO 2 column in the NCP also has a transition from the increasing trend to decreasing trend during the summer of 2005-2016. Tropospheric NO 2 and CO column concentrations obtained from satellite observations indicate that emission reductions might be the main cause of the tropospheric O 3 decrease. Particularly, the reduction of nitrogen oxides (NO x ) is more significant, and NO 2 decreased by (0.45 ± 0.11) × 10 15 molec·cm − 2 per year in summer since 2012. However, tropospheric column HCHO shows an increase of 0.05 × 10 15 molec·cm − 2 per year during the whole period of 2005 to 2016. An O 3 -NO x -VOC sensitivity experiment in the NCP showed that the O 3 is still in a NO x -saturated state in some heavily polluted cities, although the NO x emissions are decreasing overall. In addition to the chemical reactions, atmospheric dynamic processes also have an effect on tropospheric O 3 . Finally, we built a model to analyze the contributions of chemical processes and dynamic processes to the tropospheric O 3 column in the NCP. For the chemical process variables, 69.73% of the observed trend of tropospheric O 3 could be explained by the NO 2 tropospheric column. erefore, the reduction of tropospheric O 3 since 2012 is associated with the reduction of NOx. For the dynamical process variables, ENSO, PV, and EASMI can explain 60.64% of the observed trend of tropospheric O 3 . is result indicates that the atmospheric circulation of the western Pacific Ocean in summer has a significant impact on the interannual trends of tropospheric O 3 in the NCP. It is also found that chemical processes had a more important impact on interannual tropospheric O 3 than dynamic processes, although the dynamic processes cannot be neglected.

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Global O<sub>3</sub>–CO correlations in a chemistry and transport model during July–August: evaluation with TES satellite observations and sensitivity to input meteorological data and emissions

Cited by 11 publications

References 75 publications

Surface ozone and its precursors at Summit, Greenland: comparison between observations and model simulations

Surface ozone and its precursors at Summit, Greenland: comparison between observations and model simulations

Evaluating the Response of Summertime Surface Sulfate to Hydroclimate Variations in the Continental United States: Role of Meteorological Inputs in the GEOS‐Chem Model

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

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