the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 12 Mar 2024
Localized injections of interactive volcanic aerosols and their climate impacts in a simple general circulation model
Abstract. A new set of standalone parameterizations is presented for simulating the injection, evolution, and radiative forcing by stratospheric volcanic aerosols against an idealized Held-Suarez-Williamson atmospheric background in the Energy Exascale Earth System Model version 2. Sulfur dioxide (SO2) and ash are injected into the atmosphere with a specified profile in the vertical, and proceed to follow a simple exponential decay. The SO2 decay is modeled as a perfect conversion to a long-living sulfate aerosol which persists in the stratosphere. All three species are implemented as tracers in the model framework, and transported by the dynamical core’s advection algorithm. The aerosols contribute simultaneously to a local heating of the stratosphere and cooling of the surface by a simple plane-parallel Beer-Lambert law applied on two zonally-symmetric radiation broadbands in the longwave and shortwave range. It is shown that the implementation parameters can be tuned to produce realistic temperature anomaly signatures of large volcanic events. In particular, results are shown for an ensemble of runs that mimic the volcanic eruption of Mt. Pinatubo in 1991. The design requires no coupling to microphysical subgrid-scale parameterizations, and thus approaches the computational affordability of prescribed-aerosol forcing strategies. The idealized simulations contain a single isolated volcanic event against a statistically uniform climate, where no background aerosols or other sources of externally-forced variability are present. This model configuration represents a simpler-to-understand tool for the development of climate source-to-impact attribution methods.
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CEC1: 'Comment on egusphere-2024-335', Astrid Kerkweg, 26 Mar 2024
Dear authors,
in my role as Executive editor of GMD, I would like to bring to your attention our Editorial version 1.2: https://www.geosci-model-dev.net/12/2215/2019/
This highlights some requirements of papers published in GMD, which is also available on the GMD website in the ‘Manuscript Types’ section: http://www.geoscientific-model-development.net/submission/manuscript_types.html
In particular, please note that for your paper, the following requirement has not been met in the Discussions paper:
- The main paper must give the model name and version number (or other unique identifier) in the title.
Please add the name and version number of the model used (E3SMv2) to the title of your manuscript.
Yours,
Astrid Kerkweg
Citation: https://doi.org/10.5194/egusphere-2024-335-CEC1 - AC3: 'Reply on CEC1', Joseph Hollowed, 06 Jun 2024
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RC1: 'Comment on egusphere-2024-335', Anonymous Referee #1, 08 Apr 2024
“General Comments”
This work represents an impressively complete description of a highly simplified GCM with the capability to simulate two specific impacts of stratospheric-volcanic injections: stratospheric warming at the altitude of the plume and surface cooling. The authors do a good job contextualizing this model in the hierarchy of complexity of climate models and present a justification for this model’s level of complexity. Generally, this article represents excellent scientific work that is significant, of high quality, and reproducible. I suggest the authors make minor revisions in two areas: (1) making a case that this model is useful for attribution and (2) specific references to the Pinatubo literature before publications. Finally, the technical presentation of the article is excellent—I have no technical corrections.
“Specific Comments”
The authors do not show that this first-order treatment of transport, temperatures, radiation, and aerosol processes create a trustworthy climate-attribution environment. One criticism, for example, might stem from a lack of a quasi-biennial oscillation in the model. This deficiency both eliminates one way in which volcanic eruptions impact circulation and one mode of dynamical variability that impacts the transport of volcanic aerosols and their precursors.
A related issue stems from the assertion that, on line 62, “the goal is not to accurately replicate any particular historical eruption”. This assertion seems at odds with the rest of the paper which is dominated by an example of tuning parameters in order replicate the specific (and unique) eruption of Pinatubo in 1991. This highly idealized setup requires tuning these parameters; the authors should clarify how this scheme could be used in a general fashion that isn’t based on tuning parameters to a specific eruption. One suggestion for future work might be to tune the parameters to some kind of average of many eruptions.
Finally, specific to the Pinatubo eruption, the authors should expand on parameter choices. Observations (especially early on) of Pinatubo are uncertain. That being said, a plume center of mass at 14km for Pinatubo is extremely low. It is implied that this is due to unrealistic plume rise observed in this system—could the authors expand on that? In a similar vein, the 30-day e-folding time used for the Pinatubo SO2 is considered fairly uncertain—faster e-folding times (23±5 days or 25±5 days depending on choice of dataset) have been proposed (Guo et al., 2004, https://doi.org/10.1029/2003GC000654).
"Technical Corrections"
The study is excellently presented. No noticed technical errors.
Citation: https://doi.org/10.5194/egusphere-2024-335-RC1 - AC2: 'Reply on RC1', Joseph Hollowed, 06 Jun 2024
-
RC2: 'Comment on egusphere-2024-335', Matthew Toohey, 21 Apr 2024
General comments:
This paper describes a new parameterization used to simulate volcanic stratospheric aerosol processes in an idealized Held-Suarez-Williamson atmospheric general circulation model. The aerosol transport is based on advected tracers, producing a time evolving 3D aerosol field. The study introduces a physically motivated scheme to couple the radiative effects of the aerosols to the model dynamics, producing an idealized but self-consistent coupling between the aerosol radiation and the model dynamics. The scheme thus provides a novel method of simulating stratospheric aerosol, which is highly computationally efficient compared to comprehensive prognostic aerosol models while also avoiding the decoupling between dynamics and aerosol properties inherent in prescribed aerosol forcing techniques.
The description of the aerosol scheme is extremely well done. The motivation is well described, the physical basis of the parametrizations detailed with enviable clarity, and the results from an ensemble set of simulations of a Pinatubo-like sulfur injection expertly presented.
My only more general comment relates to the lack of any mention of the Brewer-Dobson circulation (BDC), which is the main process which controls the transport and spread of stratospheric aerosol. Around line 496, some discussion of the tropospheric large scale circulation is present, which may be relevant to the simulations given the rather low injection height used in the “Pinatubo-like” simulations, but the general utility of this model set-up will depend in part on the fidelity of the BDC: in terms of general features like isolation of the tropical pipe, large-scale mixing in the extratropical stratosphere, and polar subsidence. If an assessment of the stratospheric meridional circulation in the HSW model configuration is given in other studies, it would be useful to summarize some of that work in the introduction. If not, maybe the authors can provide some guidance based on their own results.
Specific comments:
L29: there are of course many different stratospheric aerosol models used by groups around the world. Therefore it could be here widen the scope of references on such model beyond one single model. A possibility might be to include a reference to a study which includes multi-model comparison (e.g., Clyne et al., 2021) and/or a model-focused review paper (e.g., Timmreck, 2012).
L150: Reference here to the HSW “forcing set” seems like a different definition of “forcing” as the term is applied to volcanic aerosol forcing.
L222: “timestep n”?
L289: I guess it should be “either absorption or scattering” or “absorption and scattering”, the latter being more generally accurate.
L300: Probably useful to specify you refer specifically to the SW AOD here. There is also a LW AOD even if it isn’t directly considered.
L328: It would be good to be explicit about ignoring heating from near-IR solar radiation which was shown by Stenchikov et al. (1998) to be a contributing factor to the total aerosol heating.
L446: missing “we” in sentence
Fig. 7 caption describes time axis as “time since eruption” which appears inaccurate.
Fig. 8 caption: the black marker should be said to denote the time and latitude of injection.
L558: here and/or in introduction, it would be useful to make reference to the work of DallaSanta et al., (2019) who used a model hierarchy to investigate the dynamical impacts of volcanic forcing, using a much simpler prescribed aerosol forcing.
L566: A stratovolcano is a particular type of volcano, not one that produces injections of sulfur to the stratosphere.
L588: a little copy editing required
References:
Clyne, M., Lamarque, J. F., Mills, M. J., Khodri, M., Ball, W., Bekki, S., Dhomse, S. S., Lebas, N., Mann, G., Marshall, L., Niemeier, U., Poulain, V., Robock, A., Rozanov, E., Schmidt, A., Stenke, A., Sukhodolov, T., Timmreck, C., Toohey, M., Tummon, F., Zanchettin, D., Zhu, Y., and Toon, O. B.: Model physics and chemistry causing intermodel disagreement within the VolMIP-Tambora Interactive Stratospheric Aerosol ensemble, Atmos. Chem. Phys., 21, 3317–3343, https://doi.org/10.5194/ACP-21-3317-2021, 2021.
Dallasanta, K., Gerber, E. P., and Toohey, M.: The circulation response to volcanic eruptions: The key roles of stratospheric warming and eddy interactions, J. Clim., 32, https://doi.org/10.1175/JCLI-D-18-0099.1, 2019.Stenchikov, G. L., Kirchner, I., Robock, A., Graf, H.-F., Antuña, J. C., Grainger, R. G., Lambert, A., and Thomason, L.: Radiative forcing from the 1991 Mount Pinatubo volcanic eruption, J. Geophys. Res., 103, 13837–13857, https://doi.org/10.1029/98JD00693, 1998.
Timmreck, C.: Modeling the climatic effects of large explosive volcanic eruptions, Wiley Interdiscip. Rev. Clim. Chang., 3, 545–564, https://doi.org/10.1002/wcc.192, 2012.Citation: https://doi.org/10.5194/egusphere-2024-335-RC2 - AC1: 'Reply on RC2', Joseph Hollowed, 06 Jun 2024
Status: closed
-
CEC1: 'Comment on egusphere-2024-335', Astrid Kerkweg, 26 Mar 2024
Dear authors,
in my role as Executive editor of GMD, I would like to bring to your attention our Editorial version 1.2: https://www.geosci-model-dev.net/12/2215/2019/
This highlights some requirements of papers published in GMD, which is also available on the GMD website in the ‘Manuscript Types’ section: http://www.geoscientific-model-development.net/submission/manuscript_types.html
In particular, please note that for your paper, the following requirement has not been met in the Discussions paper:
- The main paper must give the model name and version number (or other unique identifier) in the title.
Please add the name and version number of the model used (E3SMv2) to the title of your manuscript.
Yours,
Astrid Kerkweg
Citation: https://doi.org/10.5194/egusphere-2024-335-CEC1 - AC3: 'Reply on CEC1', Joseph Hollowed, 06 Jun 2024
-
RC1: 'Comment on egusphere-2024-335', Anonymous Referee #1, 08 Apr 2024
“General Comments”
This work represents an impressively complete description of a highly simplified GCM with the capability to simulate two specific impacts of stratospheric-volcanic injections: stratospheric warming at the altitude of the plume and surface cooling. The authors do a good job contextualizing this model in the hierarchy of complexity of climate models and present a justification for this model’s level of complexity. Generally, this article represents excellent scientific work that is significant, of high quality, and reproducible. I suggest the authors make minor revisions in two areas: (1) making a case that this model is useful for attribution and (2) specific references to the Pinatubo literature before publications. Finally, the technical presentation of the article is excellent—I have no technical corrections.
“Specific Comments”
The authors do not show that this first-order treatment of transport, temperatures, radiation, and aerosol processes create a trustworthy climate-attribution environment. One criticism, for example, might stem from a lack of a quasi-biennial oscillation in the model. This deficiency both eliminates one way in which volcanic eruptions impact circulation and one mode of dynamical variability that impacts the transport of volcanic aerosols and their precursors.
A related issue stems from the assertion that, on line 62, “the goal is not to accurately replicate any particular historical eruption”. This assertion seems at odds with the rest of the paper which is dominated by an example of tuning parameters in order replicate the specific (and unique) eruption of Pinatubo in 1991. This highly idealized setup requires tuning these parameters; the authors should clarify how this scheme could be used in a general fashion that isn’t based on tuning parameters to a specific eruption. One suggestion for future work might be to tune the parameters to some kind of average of many eruptions.
Finally, specific to the Pinatubo eruption, the authors should expand on parameter choices. Observations (especially early on) of Pinatubo are uncertain. That being said, a plume center of mass at 14km for Pinatubo is extremely low. It is implied that this is due to unrealistic plume rise observed in this system—could the authors expand on that? In a similar vein, the 30-day e-folding time used for the Pinatubo SO2 is considered fairly uncertain—faster e-folding times (23±5 days or 25±5 days depending on choice of dataset) have been proposed (Guo et al., 2004, https://doi.org/10.1029/2003GC000654).
"Technical Corrections"
The study is excellently presented. No noticed technical errors.
Citation: https://doi.org/10.5194/egusphere-2024-335-RC1 - AC2: 'Reply on RC1', Joseph Hollowed, 06 Jun 2024
-
RC2: 'Comment on egusphere-2024-335', Matthew Toohey, 21 Apr 2024
General comments:
This paper describes a new parameterization used to simulate volcanic stratospheric aerosol processes in an idealized Held-Suarez-Williamson atmospheric general circulation model. The aerosol transport is based on advected tracers, producing a time evolving 3D aerosol field. The study introduces a physically motivated scheme to couple the radiative effects of the aerosols to the model dynamics, producing an idealized but self-consistent coupling between the aerosol radiation and the model dynamics. The scheme thus provides a novel method of simulating stratospheric aerosol, which is highly computationally efficient compared to comprehensive prognostic aerosol models while also avoiding the decoupling between dynamics and aerosol properties inherent in prescribed aerosol forcing techniques.
The description of the aerosol scheme is extremely well done. The motivation is well described, the physical basis of the parametrizations detailed with enviable clarity, and the results from an ensemble set of simulations of a Pinatubo-like sulfur injection expertly presented.
My only more general comment relates to the lack of any mention of the Brewer-Dobson circulation (BDC), which is the main process which controls the transport and spread of stratospheric aerosol. Around line 496, some discussion of the tropospheric large scale circulation is present, which may be relevant to the simulations given the rather low injection height used in the “Pinatubo-like” simulations, but the general utility of this model set-up will depend in part on the fidelity of the BDC: in terms of general features like isolation of the tropical pipe, large-scale mixing in the extratropical stratosphere, and polar subsidence. If an assessment of the stratospheric meridional circulation in the HSW model configuration is given in other studies, it would be useful to summarize some of that work in the introduction. If not, maybe the authors can provide some guidance based on their own results.
Specific comments:
L29: there are of course many different stratospheric aerosol models used by groups around the world. Therefore it could be here widen the scope of references on such model beyond one single model. A possibility might be to include a reference to a study which includes multi-model comparison (e.g., Clyne et al., 2021) and/or a model-focused review paper (e.g., Timmreck, 2012).
L150: Reference here to the HSW “forcing set” seems like a different definition of “forcing” as the term is applied to volcanic aerosol forcing.
L222: “timestep n”?
L289: I guess it should be “either absorption or scattering” or “absorption and scattering”, the latter being more generally accurate.
L300: Probably useful to specify you refer specifically to the SW AOD here. There is also a LW AOD even if it isn’t directly considered.
L328: It would be good to be explicit about ignoring heating from near-IR solar radiation which was shown by Stenchikov et al. (1998) to be a contributing factor to the total aerosol heating.
L446: missing “we” in sentence
Fig. 7 caption describes time axis as “time since eruption” which appears inaccurate.
Fig. 8 caption: the black marker should be said to denote the time and latitude of injection.
L558: here and/or in introduction, it would be useful to make reference to the work of DallaSanta et al., (2019) who used a model hierarchy to investigate the dynamical impacts of volcanic forcing, using a much simpler prescribed aerosol forcing.
L566: A stratovolcano is a particular type of volcano, not one that produces injections of sulfur to the stratosphere.
L588: a little copy editing required
References:
Clyne, M., Lamarque, J. F., Mills, M. J., Khodri, M., Ball, W., Bekki, S., Dhomse, S. S., Lebas, N., Mann, G., Marshall, L., Niemeier, U., Poulain, V., Robock, A., Rozanov, E., Schmidt, A., Stenke, A., Sukhodolov, T., Timmreck, C., Toohey, M., Tummon, F., Zanchettin, D., Zhu, Y., and Toon, O. B.: Model physics and chemistry causing intermodel disagreement within the VolMIP-Tambora Interactive Stratospheric Aerosol ensemble, Atmos. Chem. Phys., 21, 3317–3343, https://doi.org/10.5194/ACP-21-3317-2021, 2021.
Dallasanta, K., Gerber, E. P., and Toohey, M.: The circulation response to volcanic eruptions: The key roles of stratospheric warming and eddy interactions, J. Clim., 32, https://doi.org/10.1175/JCLI-D-18-0099.1, 2019.Stenchikov, G. L., Kirchner, I., Robock, A., Graf, H.-F., Antuña, J. C., Grainger, R. G., Lambert, A., and Thomason, L.: Radiative forcing from the 1991 Mount Pinatubo volcanic eruption, J. Geophys. Res., 103, 13837–13857, https://doi.org/10.1029/98JD00693, 1998.
Timmreck, C.: Modeling the climatic effects of large explosive volcanic eruptions, Wiley Interdiscip. Rev. Clim. Chang., 3, 545–564, https://doi.org/10.1002/wcc.192, 2012.Citation: https://doi.org/10.5194/egusphere-2024-335-RC2 - AC1: 'Reply on RC2', Joseph Hollowed, 06 Jun 2024
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Christiane Jablonowski
Hunter Y. Brown
Benjamin R. Hillman
Diana L. Bull
Joseph L. Hart
Large volcanic eruptions deposit material into the upper-atmosphere, which is capable of altering temperature and wind patterns of the Earth's atmosphere for years following. This research describes a new method of simulating these effects in an idealized, efficient atmospheric model. A volcanic eruption of sulfur dioxide is described with a simplified set of physical rules, which eventually cools the planetary surface. This model has been designed as a testbed for climate attribution studies.
Large volcanic eruptions deposit material into the upper-atmosphere, which is capable of...