the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 31 Aug 2022
Incorporation of aerosols into the COSPv2 satellite lidar simulator for climate model evaluation
Abstract. Aerosols have a large impact on climate, air quality, and biogeochemical cycles. Their concentrations are highly variable in space and time, and a key variability is in their vertical distribution, because it influences atmospheric heating profiles, aerosols life-time and, as a result, surface concentrations, and because it has an impact on aerosol-cloud interactions. On the side of model-oriented aerosols research, using a lidar aerosol simulator ensures consistent comparisons between the modeled aerosols and the observed aerosols. In the current study, we present the lidar aerosol simulator implemented within the COSPv2 satellite lidar simulator. We estimate the total attenuated backscattered signal (ATB) and the scattering ratios (SR) that would be observed at 532 nm by the lidar CALIOP overflying the atmosphere predicted by the E3SMv1 climate model. The simulator performs the computations at the same vertical resolution as the CALIOP lidar, making use of aerosol optics from the E3SMv1 model as inputs, and assuming that aerosols are uniformly distributed horizontally within each model grid-box. It applies a cloud masking and an aerosol detection threshold, to get the ATB and SR profiles that would be observed above clouds by CALIOP with its actual aerosol detection capability. Our comparison shows that the aerosol distribution simulated at a seasonal timescale is generally in good agreement with observations, with however a discrepancy in the Southern Hemisphere, as the observed SR maximum is not reproduced in simulations there. Comparison between cloud-screened and non cloud-screened computed SRs shows little differences, indicating that the cloud screening by potentially incorrect model clouds does not affect the mean aerosol signal averaged over a season. Consequently, the differences between observed and simulated SR values are not due to sampling errors, and allow to point out some weaknesses in the aerosol representation in models. The use of lidar observations at several wavelengths can give further indication on the nature of the aerosols that need to be improved.
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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
(3004 KB)
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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
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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CEC1: 'Comment on egusphere-2022-438', Juan Antonio Añel, 21 Sep 2022
Dear authors,
Unfortunately, after checking your manuscript, it has come to our attention that it does not comply with our "Code and Data Policy".
https://www.geoscientific-model-development.net/policies/code_and_data_policy.htmlYou have archived your code on GitHub. However, GitHub is not a suitable repository. GitHub itself instructs authors to use other alternatives for long-term archival and publishing, such as Zenodo. Therefore, please, publish your code in one of the appropriate repositories, and reply to this comment with the relevant information (link and DOI) as soon as possible, as it should be available for the Discussions stage.
Also, you cite two repositories we can not accept for data. Neither NASA web servers nor ResearchGate are acceptable, as our policy states, and they are unsuitable for long-term archival. Indeed, ResearchGate (as GitHub) is property of a private company that can terminate the service at any moment without explanations. Therefore, please, move the data to one of the suitable repositories according to our policy.
Please, be aware that failing to comply promptly with this request could result in rejecting your manuscript for publication.
Juan A. AñelGeosci. Model Dev. Exec. EditorCitation: https://doi.org/10.5194/egusphere-2022-438-CEC1 -
AC1: 'Reply on CEC1', Marine Bonazzola, 23 Sep 2022
Dear Editor,
The code has now been transferred to zenodo, with the following DOI : DOI 10.5281/zenodo.7107428
The two data files (ATB and SR vertical profiles from CALIOP after data processing) have now the DOI : 10.5281/zenodo.7107232 and 10.5281/zenodo.7107162 respectively.
Concerning the CALIOP lidar level L1.5 data, I think creating a specific DOI is not necessary as these data are of free access on the NASA website. In the section "data avaibility" the reference is given for these data.
I hope these changes meet your expectations.
Best regards,
Marine Bonazzola
Citation: https://doi.org/10.5194/egusphere-2022-438-AC1 -
CEC2: 'Reply on AC1', Juan Antonio Añel, 26 Sep 2022
Dear authors,
Many thanks for replying to the comment. Publishing the processed data used in the study is enough. However, note that if the L1.5 was necessary, NASA servers would not be trustable. It is a common mistake to think that every renowned institution is trustable for long-term data archival.
Regards,
Juan A. Añel
Geosci. Model Dev. Executive Editor
Citation: https://doi.org/10.5194/egusphere-2022-438-CEC2
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CEC2: 'Reply on AC1', Juan Antonio Añel, 26 Sep 2022
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AC1: 'Reply on CEC1', Marine Bonazzola, 23 Sep 2022
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RC1: 'Comment on egusphere-2022-438', Duncan Watson-Parris, 03 Oct 2022
The authors present a significant addition to the COSPv2 satellite simulator package to include the simulation of CALIOP aerosol retrievals from model variables. Previous work has shown the importance of considering the detection sensitivity of CALIOP when comparing with modelled aerosol backscatter and extinction and this work provides a neat model-agnostic solution. This is a valuable contribution which has been well validated and I feel is suitable for publication in GMD after some amendments.
My main concerns with the current presentation of the manuscript is that the numbered variable (SR_0, 1, etc) names make reading and following the text very difficult, especially in legends and captions. I would strongly suggest that these are renamed to something more easily understandable such as SR_noclouds, SR_detectable, etc. both in the paper and in the code (if applicable). My second main concern is that I can’t find this code contribution in the COSPv2 codebase linked to in the manuscript. Has this been merged into the code? I would appreciate visibility of the code (the specific files / commit) in order to provide a more detailed review.
The only major scientific comment I have is that I seem to remember the CALIOP aerosol detection threshold depends on the presence of cloud. I.e., if there is thin attenuating cloud aloft, or a thick layer of low cloud this would change the detection threshold. As far as I can see this isn’t accounted for, which is understandable since it may not be easy to quantify (and models won’t suffer from it), but it should be mentioned as a possible source of discrepancy in the combined EXT_3 variable.
While generally well written and structured the introduction is missing some citations and a bit more context (detailed below). Also, the discussion section contains results on the effect of cloud screening, on page 18 through to line 18 on page 21, which should please be moved to the results section (or in an Appendix).
Minor comments
- P2L24-25: Please rephrase, perhaps you mean ‘variety of aerosol research questions’.
- P2L24-25: Please provide citations rather than a URL.
- P2L31-35: Citation needed
- P2L35-37: Citation needed
- P3L6-8: Citation needed
- P3L8: This doesn’t make sense and needs rephrasing
- P3L17: Add a full stop after ‘model’ to break up this long sentence?
- P3L36: “(from the cloud lidar simulator but not only)” -> (from not only the cloud lidar simulator)
- P4 Figure 1 caption: Everything after the first sentence should be in the main text rather than the caption.
- P4L18: Please provide citations for the Rayleigh scattering expressions
- P5L19: ‘simple’ -> ‘single’
- P5L29: Is this every radiation timestep or every model timestep? Please clarify
- P5L42: Does this interpolation also work for models on pressure levels?
- P7L20: Please place the Figure 1 caption text here.
- P7L24: ‘model+aerosol’ -> model and aerosol
- P7L43: Citation
- P9L4-5: Setting the SR=1 is equivalent to setting the aerosol backscatter to zero which may be a reasonable assumption but should be done carefully – particularly when averaging over large regions of tenuous aerosol (see e.g., Watson-Parris et al. 2018). Please make this assumption explicit in the text.
- In addition to using more descriptive variable names (especially in figure titles), please also use the full model name in the figure legends (e.g. Fig. 10)
- P22L17: -> …modes has been used interactively for almost two decades…
- P23L16: As a co-author, presumably Nick doesn’t need to be acknowledged ï
Citation: https://doi.org/10.5194/egusphere-2022-438-RC1 -
RC2: 'Comment on egusphere-2022-438', Anonymous Referee #2, 10 Oct 2022
Bonazzola et al extend the well-known COSP satellite cloud simulator with a package designed to retrieve vertically-resolved aerosol information. This is a natural and valuable addition to COSP, and is likely to find wide uptake.
The study also indicates that accounting for clouds when calculating backscatter ratios isn’t necessary to achieve a good comparison over longer time periods. This is a valuable result in itself, as it suggests even models with poor cloud representation can benefit from using COSP aerosol evaluation.
I have identified no scientific concerns.
Major comments
I can’t find the aerosol-related additions to COSP on git nor on zenodo. Could the authors be more specific about which routines have changed, perhaps even going as far as providing a diff file?
The word ‘aerosol’ is effectively already plural, as it refers to the population of particles and not a single particle. Thus ‘aerosols’ is unnecessary. I suggest correcting throughout the manuscript, but at the same time acknowledge that ‘aerosols’ is becoming widespread.
Readability in many places could be significantly improved with some editing. Many sentences are quite awkward to read and follow.
Minor comments
Abstract, line 4: The clause ‘and because it has an impact on aerosol-cloud interactions’ seems to be out of place. The sentence in its entirety is hard to follow.
Abstract, sentence starting on line 12: ‘It applies…’, please clarify what ‘it’ is.
Abstract, line 15: ‘discrepancy in the Southern Hemisphere’. Is it possible to be more specific? The Southern Hemisphere is half the globe. Perhaps Southern Ocean is what is being referred to?
Page 2, line 5: not all greenhouse gases are long-lived, e.g. ozone. Suggest adding ‘long-lived’ before greenhouse gases
Several of the Figures comparing SR0, SR1 etc: It might be easier for the reader to interpret the plots if they were presented as difference plots, e.g. difference to SR0. As presented, the reader finds themselves looking for subtle changes in color in order to derive value from a figure. Additionally the chosen color palette would present difficulties for anyone with color blindness.
Citation: https://doi.org/10.5194/egusphere-2022-438-RC2
Interactive discussion
Status: closed
-
CEC1: 'Comment on egusphere-2022-438', Juan Antonio Añel, 21 Sep 2022
Dear authors,
Unfortunately, after checking your manuscript, it has come to our attention that it does not comply with our "Code and Data Policy".
https://www.geoscientific-model-development.net/policies/code_and_data_policy.htmlYou have archived your code on GitHub. However, GitHub is not a suitable repository. GitHub itself instructs authors to use other alternatives for long-term archival and publishing, such as Zenodo. Therefore, please, publish your code in one of the appropriate repositories, and reply to this comment with the relevant information (link and DOI) as soon as possible, as it should be available for the Discussions stage.
Also, you cite two repositories we can not accept for data. Neither NASA web servers nor ResearchGate are acceptable, as our policy states, and they are unsuitable for long-term archival. Indeed, ResearchGate (as GitHub) is property of a private company that can terminate the service at any moment without explanations. Therefore, please, move the data to one of the suitable repositories according to our policy.
Please, be aware that failing to comply promptly with this request could result in rejecting your manuscript for publication.
Juan A. AñelGeosci. Model Dev. Exec. EditorCitation: https://doi.org/10.5194/egusphere-2022-438-CEC1 -
AC1: 'Reply on CEC1', Marine Bonazzola, 23 Sep 2022
Dear Editor,
The code has now been transferred to zenodo, with the following DOI : DOI 10.5281/zenodo.7107428
The two data files (ATB and SR vertical profiles from CALIOP after data processing) have now the DOI : 10.5281/zenodo.7107232 and 10.5281/zenodo.7107162 respectively.
Concerning the CALIOP lidar level L1.5 data, I think creating a specific DOI is not necessary as these data are of free access on the NASA website. In the section "data avaibility" the reference is given for these data.
I hope these changes meet your expectations.
Best regards,
Marine Bonazzola
Citation: https://doi.org/10.5194/egusphere-2022-438-AC1 -
CEC2: 'Reply on AC1', Juan Antonio Añel, 26 Sep 2022
Dear authors,
Many thanks for replying to the comment. Publishing the processed data used in the study is enough. However, note that if the L1.5 was necessary, NASA servers would not be trustable. It is a common mistake to think that every renowned institution is trustable for long-term data archival.
Regards,
Juan A. Añel
Geosci. Model Dev. Executive Editor
Citation: https://doi.org/10.5194/egusphere-2022-438-CEC2
-
CEC2: 'Reply on AC1', Juan Antonio Añel, 26 Sep 2022
-
AC1: 'Reply on CEC1', Marine Bonazzola, 23 Sep 2022
-
RC1: 'Comment on egusphere-2022-438', Duncan Watson-Parris, 03 Oct 2022
The authors present a significant addition to the COSPv2 satellite simulator package to include the simulation of CALIOP aerosol retrievals from model variables. Previous work has shown the importance of considering the detection sensitivity of CALIOP when comparing with modelled aerosol backscatter and extinction and this work provides a neat model-agnostic solution. This is a valuable contribution which has been well validated and I feel is suitable for publication in GMD after some amendments.
My main concerns with the current presentation of the manuscript is that the numbered variable (SR_0, 1, etc) names make reading and following the text very difficult, especially in legends and captions. I would strongly suggest that these are renamed to something more easily understandable such as SR_noclouds, SR_detectable, etc. both in the paper and in the code (if applicable). My second main concern is that I can’t find this code contribution in the COSPv2 codebase linked to in the manuscript. Has this been merged into the code? I would appreciate visibility of the code (the specific files / commit) in order to provide a more detailed review.
The only major scientific comment I have is that I seem to remember the CALIOP aerosol detection threshold depends on the presence of cloud. I.e., if there is thin attenuating cloud aloft, or a thick layer of low cloud this would change the detection threshold. As far as I can see this isn’t accounted for, which is understandable since it may not be easy to quantify (and models won’t suffer from it), but it should be mentioned as a possible source of discrepancy in the combined EXT_3 variable.
While generally well written and structured the introduction is missing some citations and a bit more context (detailed below). Also, the discussion section contains results on the effect of cloud screening, on page 18 through to line 18 on page 21, which should please be moved to the results section (or in an Appendix).
Minor comments
- P2L24-25: Please rephrase, perhaps you mean ‘variety of aerosol research questions’.
- P2L24-25: Please provide citations rather than a URL.
- P2L31-35: Citation needed
- P2L35-37: Citation needed
- P3L6-8: Citation needed
- P3L8: This doesn’t make sense and needs rephrasing
- P3L17: Add a full stop after ‘model’ to break up this long sentence?
- P3L36: “(from the cloud lidar simulator but not only)” -> (from not only the cloud lidar simulator)
- P4 Figure 1 caption: Everything after the first sentence should be in the main text rather than the caption.
- P4L18: Please provide citations for the Rayleigh scattering expressions
- P5L19: ‘simple’ -> ‘single’
- P5L29: Is this every radiation timestep or every model timestep? Please clarify
- P5L42: Does this interpolation also work for models on pressure levels?
- P7L20: Please place the Figure 1 caption text here.
- P7L24: ‘model+aerosol’ -> model and aerosol
- P7L43: Citation
- P9L4-5: Setting the SR=1 is equivalent to setting the aerosol backscatter to zero which may be a reasonable assumption but should be done carefully – particularly when averaging over large regions of tenuous aerosol (see e.g., Watson-Parris et al. 2018). Please make this assumption explicit in the text.
- In addition to using more descriptive variable names (especially in figure titles), please also use the full model name in the figure legends (e.g. Fig. 10)
- P22L17: -> …modes has been used interactively for almost two decades…
- P23L16: As a co-author, presumably Nick doesn’t need to be acknowledged ï
Citation: https://doi.org/10.5194/egusphere-2022-438-RC1 -
RC2: 'Comment on egusphere-2022-438', Anonymous Referee #2, 10 Oct 2022
Bonazzola et al extend the well-known COSP satellite cloud simulator with a package designed to retrieve vertically-resolved aerosol information. This is a natural and valuable addition to COSP, and is likely to find wide uptake.
The study also indicates that accounting for clouds when calculating backscatter ratios isn’t necessary to achieve a good comparison over longer time periods. This is a valuable result in itself, as it suggests even models with poor cloud representation can benefit from using COSP aerosol evaluation.
I have identified no scientific concerns.
Major comments
I can’t find the aerosol-related additions to COSP on git nor on zenodo. Could the authors be more specific about which routines have changed, perhaps even going as far as providing a diff file?
The word ‘aerosol’ is effectively already plural, as it refers to the population of particles and not a single particle. Thus ‘aerosols’ is unnecessary. I suggest correcting throughout the manuscript, but at the same time acknowledge that ‘aerosols’ is becoming widespread.
Readability in many places could be significantly improved with some editing. Many sentences are quite awkward to read and follow.
Minor comments
Abstract, line 4: The clause ‘and because it has an impact on aerosol-cloud interactions’ seems to be out of place. The sentence in its entirety is hard to follow.
Abstract, sentence starting on line 12: ‘It applies…’, please clarify what ‘it’ is.
Abstract, line 15: ‘discrepancy in the Southern Hemisphere’. Is it possible to be more specific? The Southern Hemisphere is half the globe. Perhaps Southern Ocean is what is being referred to?
Page 2, line 5: not all greenhouse gases are long-lived, e.g. ozone. Suggest adding ‘long-lived’ before greenhouse gases
Several of the Figures comparing SR0, SR1 etc: It might be easier for the reader to interpret the plots if they were presented as difference plots, e.g. difference to SR0. As presented, the reader finds themselves looking for subtle changes in color in order to derive value from a figure. Additionally the chosen color palette would present difficulties for anyone with color blindness.
Citation: https://doi.org/10.5194/egusphere-2022-438-RC2
Peer review completion
Journal article(s) based on this preprint
Data sets
CALIOP lidar level L1.5 profiles NASA Langley Atmospheric Science Data Center DAAC https://doi.org/10.5067/CALIOP/CALIPSO/LID_L15-STANDARD-V1-00
CALIOP SR profiles Marine Bonazzola https://doi.org/10.13140/RG.2.2.32924.97929
CALIOP ATB profiles Marine Bonazzola https://doi.org/10.13140/RG.2.2.27891.81442
Model code and software
COSPv2 simulator Rodrigo Guzman, Hélène Chepfer https://github.com/CFMIP/COSPv2.0
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- 1
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Marine Bonazzola
Hélène Chepfer
Po-Lun Ma
Johannes Quaas
David M. Winker
Artem Feofilov
Nick Schutgens
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(3004 KB) - Metadata XML