the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 28 Nov 2022
Variable effects of spatial resolution on modeling of nitrogen oxides
Abstract. The lifetime and concentration of nitrogen oxides (NOx) are susceptible to non-linear production and loss, and con- sequently to the resolution of a chemical transport model (CTM). Here we use the GEOS-Chem CTM in its high performance implementation (GCHP) to investigate NOx simulations over the eastern United States across a wide range of resolutions (13–181 km). Following increasing grid size, daytime surface NOx concentrations over July 2015 generally decrease over the Great Lakes (GL) region and increase over the Southern States (SS), yielding regional biases (181 km vs. 13 km) of −18 % to 9 %; meanwhile hydrogen oxide radicals (HOx) increase over both regions, consistent with their different chemical regimes. Night- time titration of ozone by surface nitric oxide (NO) was found to be more efficient at coarser resolutions, leading to longer NOx lifetimes and higher surface concentrations of nitrogen dioxide (NO2) over the GL in January 2015. The tropospheric NO2 column density at typical afternoon satellite overpass time has spatially more coherent negative biases (e.g., −10 % over the GL) at coarser resolutions in July, which reversed the positive biases of surface NOx over the SS. The reduced NO2 aloft (> 1 km altitude) at coarser resolutions was attributable to the enhanced HOx that intrudes into the upper troposphere. Application of coarse resolution simulations for interpreting satellite NO2 columns will generally underestimate surface NO2 over the GL and overestimate surface NO2 over the SS in summer, while uniformly overestimating NOx emissions over both regions. This study significantly broadens understanding of factors contributing to NOx resolution effects, and the role of fine resolution to accurately simulate and interpret NOx and its relevance to air quality.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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Supplement
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(4350 KB) - Metadata XML
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Supplement
(2828 KB) - BibTeX
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
- RC1: 'Comment on egusphere-2022-1191', Anonymous Referee #1, 22 Dec 2022
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RC2: 'Comment on egusphere-2022-1191', Anonymous Referee #2, 23 Dec 2022
The study by Li et al. evaluates the dependency of NOx-chemistry on spatial resolution at different regions with contrast chemical regime, time (daytime vs nighttime, winter vs summer), and vertical layers. The authors have made use of the new capability of a state-of-art chemical transport model GEOS-Chem to conduct the simulations at different resolution. The different regional and temporal NOx-resolution dependences are well explained by the NOx-HOx-ozone chemistry, and the implications for satellite application has been discussed. Overall this is a novel, comprehensive, and nicely-designed study, and is clearly-written. The figures and analyses are high quality. The results have important scientific implications, not only for application of satellite observations to infer NOx concentration and emissions, but also for modelers to understand model bias of NOx and ozone. I recommend publication in ACP after minor revision.
The overall mechanisms to explain NOx-resolution dependency are convincing, but I wonder to whether other factors, such as the difference in meteorological fields at different resolution, may contribute to the NOx-resolution dependency. I understand this might be hard to quantitatively explore but some discussions are beneficial.
Some technical issues
(1) Line 79: Are the EDGAR emissions in line with NEI? Why not use EDGAR inventory for VOCs as well?
(2) Line 135: Would it be helpful to plot the spatial distribution of chemical lifetime of NOx and the change with resolutions?
(3) Figure 3: I spend some minutes on understanding Fig.3 and finally find out that I misunderstand the dashed lines (in particular for ozone) as absolute values of concentrations for the coarser resolution. I feel that other readers may be confused as well so I would suggest the authors disregard the relative change in the right axis.
(4) I also feel that I have to jump between the main text and supplementary materials during reading. Please consider moving important figures from SI to the main text.
Citation: https://doi.org/10.5194/egusphere-2022-1191-RC2 -
AC1: 'Reply to Review Comments (egusphere-2022-1191)', Chi Li, 20 Feb 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2022/egusphere-2022-1191/egusphere-2022-1191-AC1-supplement.pdf
Interactive discussion
Status: closed
- RC1: 'Comment on egusphere-2022-1191', Anonymous Referee #1, 22 Dec 2022
-
RC2: 'Comment on egusphere-2022-1191', Anonymous Referee #2, 23 Dec 2022
The study by Li et al. evaluates the dependency of NOx-chemistry on spatial resolution at different regions with contrast chemical regime, time (daytime vs nighttime, winter vs summer), and vertical layers. The authors have made use of the new capability of a state-of-art chemical transport model GEOS-Chem to conduct the simulations at different resolution. The different regional and temporal NOx-resolution dependences are well explained by the NOx-HOx-ozone chemistry, and the implications for satellite application has been discussed. Overall this is a novel, comprehensive, and nicely-designed study, and is clearly-written. The figures and analyses are high quality. The results have important scientific implications, not only for application of satellite observations to infer NOx concentration and emissions, but also for modelers to understand model bias of NOx and ozone. I recommend publication in ACP after minor revision.
The overall mechanisms to explain NOx-resolution dependency are convincing, but I wonder to whether other factors, such as the difference in meteorological fields at different resolution, may contribute to the NOx-resolution dependency. I understand this might be hard to quantitatively explore but some discussions are beneficial.
Some technical issues
(1) Line 79: Are the EDGAR emissions in line with NEI? Why not use EDGAR inventory for VOCs as well?
(2) Line 135: Would it be helpful to plot the spatial distribution of chemical lifetime of NOx and the change with resolutions?
(3) Figure 3: I spend some minutes on understanding Fig.3 and finally find out that I misunderstand the dashed lines (in particular for ozone) as absolute values of concentrations for the coarser resolution. I feel that other readers may be confused as well so I would suggest the authors disregard the relative change in the right axis.
(4) I also feel that I have to jump between the main text and supplementary materials during reading. Please consider moving important figures from SI to the main text.
Citation: https://doi.org/10.5194/egusphere-2022-1191-RC2 -
AC1: 'Reply to Review Comments (egusphere-2022-1191)', Chi Li, 20 Feb 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2022/egusphere-2022-1191/egusphere-2022-1191-AC1-supplement.pdf
Peer review completion
Journal article(s) based on this preprint
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Randall V. Martin
Ronald C. Cohen
Liam Bindle
Dandan Zhang
Deepangsu Chatterjee
Hongjian Weng
Jintai Lin
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(4350 KB) - Metadata XML
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Supplement
(2828 KB) - BibTeX
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- Final revised paper