the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 26 Jun 2024
An updated aerosol simulation in the Community Earth System Model (v2.1.3): dust and marine aerosol emissions and secondary organic aerosol formation
Abstract. Aerosols constitute important substance components of the Earth's atmosphere and have a profound influence on climate dynamics, radiative properties, and biogeochemical processes. Here we develop updated emission schemes for dust, sea-salt, and marine primary organic aerosols (MPOA) and augment formation reactions for secondary organic aerosol (SOA) by introducing updated parameterizations within the Community Earth System Model (CESM; version 2.1.3). The modified scheme shifts the original hotspot-like dust emission to a more continuous distribution, improving the dust aerosol optical depth (DAOD) simulations at stations in North Africa and Central Asia. Also, it results in shorter dust residence time, necessary for enhancing concentration simulations downwind of dust source regions. Modifications in the sea-salt emission scheme include an update to sea surface temperature (SST) modulation and the introduction of a relative-humidity-dependent correction factor for sea-salt particle size. The effect of SST is much more significant compared to that of relative humidity. We then extend to incorporate emissions of marine primary organic aerosols (MPOA) as externally mixed with sea-salt aerosols, coupled offline with ocean component Parallel Ocean Program (POP2). The influence of phytoplankton species on modeling MPOA emissions is profound, highlighting the significance of biological diversity in shaping aerosol emissions. In addition to these emission scheme improvements, we also refine the chemical mechanisms in the model. The irreversible aqueous uptake of dicarbonyl compounds is added as a new pathway for the SOA formation in the model. These improvements enrich the capability of the CESM by using ESM’s intricate linkage between different spheres of the Earth system, thereby enabling a more comprehensive description of natural aerosol emission and chemical processes and their impacts.
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RC1: 'Comment on gmd-2024-109', Anonymous Referee #1, 25 Jul 2024
This study attempted to improve the aerosol simulation in the CESM model by updating the emission schemes for dust and marine aerosols as well as the heterogeneous chemistry of SOA formation. These updates were further supported by evaluating model results against multiple aerosols measurements. Overall, this is an important study and the overall conclusions are reasonable. I would like to recommend its publication after further revisions. In particular, the presentation quality of this manuscript should be improved. Please find my comments in the following:
In Section 2.2, it is strongly suggested to add a Table to list all the model simulations conducted in this study.
Fig.10 compared the simulated and observed sea-salt concentrations, but it looks the model performance is good. This model bias is mainly attributed to the coarse model resolution. Why is model resolution particularly critical for sea-salt simulation? In addition, the updated simulation shows improved correlation but monthly variations of sea-salt aerosols in the two simulations look like very similar. I suggest the authors to check over the calculated correlation.
As shown in Fig.15, the effects of added SOA formation pathways are notable over biogenic and biomass burning-affected region. As such, I suggest to show some seasonal variations of these effects.
In Abstract and Conclusions Sections, I strongly suggest the authors to add some quantitative conclusions that show the effects of update schemes on aerosol simulations.
The table caption should be moved to the top of each table.
I think the“CAM6-Chem” should be changed to “CAM6-chem” throughout the text.
L263: The reference for MERRA2 reanalysis data looks not correct.
L267: The “CYCLE” simulation was using CAM5 not CAM6?
L302-303: I suggest to move the introduction of model evaluation metrics after Section 2.3.
L316: Why were these two measurement sites considered here?
L461: Any updated model results from CMIP6?
L610: The authors only show the changes in global annual mean PM2.5 but attempt to link it with haze episodes. Any further evidence to support this argument?
In Fig.6, I suggest to add the location information (e.g., Latitude and longitude) of each AERONET site on the plots.
In Fig.13, to be consistent with other Figures, I suggest to also add the RMSE metric in the plot.
Citation: https://doi.org/10.5194/gmd-2024-109-RC1 -
AC1: 'Reply on RC1', Yanxu Zhang, 04 Sep 2024
The comment was uploaded in the form of a supplement: https://gmd.copernicus.org/preprints/gmd-2024-109/gmd-2024-109-AC1-supplement.pdf
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AC1: 'Reply on RC1', Yanxu Zhang, 04 Sep 2024
-
RC2: 'Comment on gmd-2024-109', Anonymous Referee #2, 05 Aug 2024
This manuscript addresses the improvement of aerosol simulations in the CESM model by revising emission schemes for dust and marine aerosols and incorporating aqueous chemistry for SOA formation. The authors present a clear and systematic approach, starting with the implementation of revised aerosol schemes, followed by the comparison of their updated simulation results with various aerosol observational measurements to evaluate their proposed simulations. In particular, the authors design sensitivity experiments in a further discussion to capture the uncertainties in the simulations of these several aerosol species. Given the focus of the study, the methodologies used, and the conclusions presented, this manuscript meets the criteria for publication in Geoscientific Model Development.
However, the manuscript in its current form requires better organization and clarity. I recommend publication after the following revisions are made:
- Page 2 Line 33: change “indicate” to “indicates”.
- Page 2 Line 43: change “is” to “are”.
- Page 2 Line 52: add comma before “and even…”.
- Page 3 Line 87: change “comprising of” to “comprising”.
- Page 3 Line 90: add “the” before “Earth system”. Change “is” to “are”.
- Page 4 Line 114: remove “the” before “Owen’s effect”.
- Page 6 Line 143: remove “By” before “corresponding to”.
- Page 6 Line 154: change “shows” to “show”.
- Page 7 Line 173: change “region” to “regions”.
- Page 8 Line 197: change “varies” to “vary”.
- Page 9 Line 226: add “the” before “majority”.
- Page 10 Line 249: change “dicarbonyls” to “dicarbonyl”.
- Page 10-11 Section 2.2: The authors mentioned that a "CYCLE" experiment, along with a case study and several other sensitivity experiments, was conducted. To enhance readability, a table-like presentation should be included.
- Page 11 Line 271: remove the article “a” before “dust events”.
- Page 11 Line 278: change “a” to “an”.
- Page 11 Line 280: change “involves” to “involve”.
- Page 12 Line 302: Two statistical metrics are mentioned here for model evaluation. A description of these two metrics should be added, and their use should be consistent in other similar time series comparisons throughout the manuscript.
- Page 17 Figure 7: The color bar needs adjustment. The current maximum value doesn't adequately represent the information in certain areas.
- Page 22 Line 524: add “a” before “comparison”.
- Page 24 Line 558: change “corresponds” to “correspond”.
Citation: https://doi.org/10.5194/gmd-2024-109-RC2 -
AC2: 'Reply on RC2', Yanxu Zhang, 04 Sep 2024
The comment was uploaded in the form of a supplement: https://gmd.copernicus.org/preprints/gmd-2024-109/gmd-2024-109-AC2-supplement.pdf
Status: closed
-
RC1: 'Comment on gmd-2024-109', Anonymous Referee #1, 25 Jul 2024
This study attempted to improve the aerosol simulation in the CESM model by updating the emission schemes for dust and marine aerosols as well as the heterogeneous chemistry of SOA formation. These updates were further supported by evaluating model results against multiple aerosols measurements. Overall, this is an important study and the overall conclusions are reasonable. I would like to recommend its publication after further revisions. In particular, the presentation quality of this manuscript should be improved. Please find my comments in the following:
In Section 2.2, it is strongly suggested to add a Table to list all the model simulations conducted in this study.
Fig.10 compared the simulated and observed sea-salt concentrations, but it looks the model performance is good. This model bias is mainly attributed to the coarse model resolution. Why is model resolution particularly critical for sea-salt simulation? In addition, the updated simulation shows improved correlation but monthly variations of sea-salt aerosols in the two simulations look like very similar. I suggest the authors to check over the calculated correlation.
As shown in Fig.15, the effects of added SOA formation pathways are notable over biogenic and biomass burning-affected region. As such, I suggest to show some seasonal variations of these effects.
In Abstract and Conclusions Sections, I strongly suggest the authors to add some quantitative conclusions that show the effects of update schemes on aerosol simulations.
The table caption should be moved to the top of each table.
I think the“CAM6-Chem” should be changed to “CAM6-chem” throughout the text.
L263: The reference for MERRA2 reanalysis data looks not correct.
L267: The “CYCLE” simulation was using CAM5 not CAM6?
L302-303: I suggest to move the introduction of model evaluation metrics after Section 2.3.
L316: Why were these two measurement sites considered here?
L461: Any updated model results from CMIP6?
L610: The authors only show the changes in global annual mean PM2.5 but attempt to link it with haze episodes. Any further evidence to support this argument?
In Fig.6, I suggest to add the location information (e.g., Latitude and longitude) of each AERONET site on the plots.
In Fig.13, to be consistent with other Figures, I suggest to also add the RMSE metric in the plot.
Citation: https://doi.org/10.5194/gmd-2024-109-RC1 -
AC1: 'Reply on RC1', Yanxu Zhang, 04 Sep 2024
The comment was uploaded in the form of a supplement: https://gmd.copernicus.org/preprints/gmd-2024-109/gmd-2024-109-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Yanxu Zhang, 04 Sep 2024
-
RC2: 'Comment on gmd-2024-109', Anonymous Referee #2, 05 Aug 2024
This manuscript addresses the improvement of aerosol simulations in the CESM model by revising emission schemes for dust and marine aerosols and incorporating aqueous chemistry for SOA formation. The authors present a clear and systematic approach, starting with the implementation of revised aerosol schemes, followed by the comparison of their updated simulation results with various aerosol observational measurements to evaluate their proposed simulations. In particular, the authors design sensitivity experiments in a further discussion to capture the uncertainties in the simulations of these several aerosol species. Given the focus of the study, the methodologies used, and the conclusions presented, this manuscript meets the criteria for publication in Geoscientific Model Development.
However, the manuscript in its current form requires better organization and clarity. I recommend publication after the following revisions are made:
- Page 2 Line 33: change “indicate” to “indicates”.
- Page 2 Line 43: change “is” to “are”.
- Page 2 Line 52: add comma before “and even…”.
- Page 3 Line 87: change “comprising of” to “comprising”.
- Page 3 Line 90: add “the” before “Earth system”. Change “is” to “are”.
- Page 4 Line 114: remove “the” before “Owen’s effect”.
- Page 6 Line 143: remove “By” before “corresponding to”.
- Page 6 Line 154: change “shows” to “show”.
- Page 7 Line 173: change “region” to “regions”.
- Page 8 Line 197: change “varies” to “vary”.
- Page 9 Line 226: add “the” before “majority”.
- Page 10 Line 249: change “dicarbonyls” to “dicarbonyl”.
- Page 10-11 Section 2.2: The authors mentioned that a "CYCLE" experiment, along with a case study and several other sensitivity experiments, was conducted. To enhance readability, a table-like presentation should be included.
- Page 11 Line 271: remove the article “a” before “dust events”.
- Page 11 Line 278: change “a” to “an”.
- Page 11 Line 280: change “involves” to “involve”.
- Page 12 Line 302: Two statistical metrics are mentioned here for model evaluation. A description of these two metrics should be added, and their use should be consistent in other similar time series comparisons throughout the manuscript.
- Page 17 Figure 7: The color bar needs adjustment. The current maximum value doesn't adequately represent the information in certain areas.
- Page 22 Line 524: add “a” before “comparison”.
- Page 24 Line 558: change “corresponds” to “correspond”.
Citation: https://doi.org/10.5194/gmd-2024-109-RC2 -
AC2: 'Reply on RC2', Yanxu Zhang, 04 Sep 2024
The comment was uploaded in the form of a supplement: https://gmd.copernicus.org/preprints/gmd-2024-109/gmd-2024-109-AC2-supplement.pdf
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