Exploring the uncertainties in the aviation soot–cirrus effect
A global aerosol–climate model, including a two-moment cloud microphysical scheme and a parametrization for aerosol-induced ice formation in cirrus clouds, is applied in order to quantify the impact of aviation soot on natural cirrus clouds. Several sensitivity experiments are performed to assess th...
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ftcopernicus:oai:publications.copernicus.org:acp94133 2023-05-15T18:18:47+02:00 Exploring the uncertainties in the aviation soot–cirrus effect Righi, Mattia Hendricks, Johannes Beer, Christof Gerhard 2021-11-30 application/pdf https://doi.org/10.5194/acp-21-17267-2021 https://acp.copernicus.org/articles/21/17267/2021/ eng eng doi:10.5194/acp-21-17267-2021 https://acp.copernicus.org/articles/21/17267/2021/ eISSN: 1680-7324 Text 2021 ftcopernicus https://doi.org/10.5194/acp-21-17267-2021 2021-12-06T17:22:31Z A global aerosol–climate model, including a two-moment cloud microphysical scheme and a parametrization for aerosol-induced ice formation in cirrus clouds, is applied in order to quantify the impact of aviation soot on natural cirrus clouds. Several sensitivity experiments are performed to assess the uncertainties in this effect related to (i) the assumptions on the ice nucleation abilities of aviation soot, (ii) the representation of vertical updrafts in the model, and (iii) the use of reanalysis data to relax the model dynamics (the so-called nudging technique). Based on the results of the model simulations, a radiative forcing from the aviation soot–cirrus effect in the range of −35 to 13 mW m −2 is quantified, depending on the assumed critical saturation ratio for ice nucleation and active fraction of aviation soot but with a confidence level below 95 % in several cases. Simple idealized experiments with prescribed vertical velocities further show that the uncertainties on this aspect of the model dynamics are critical for the investigated effect and could potentially add a factor of about 2 of further uncertainty to the model estimates of the resulting radiative forcing. The use of the nudging technique to relax model dynamics is proved essential in order to identify a statistically significant signal from the model internal variability, while simulations performed in free-running mode and with prescribed sea-surface temperatures and sea-ice concentrations are shown to be unable to provide robust estimates of the investigated effect. A comparison with analogous model studies on the aviation soot–cirrus effect show a very large model diversity, with a conspicuous lack of consensus across the various estimates, which points to the need for more in-depth analyses on the roots of such discrepancies. Text Sea ice Copernicus Publications: E-Journals Atmospheric Chemistry and Physics 21 23 17267 17289 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
A global aerosol–climate model, including a two-moment cloud microphysical scheme and a parametrization for aerosol-induced ice formation in cirrus clouds, is applied in order to quantify the impact of aviation soot on natural cirrus clouds. Several sensitivity experiments are performed to assess the uncertainties in this effect related to (i) the assumptions on the ice nucleation abilities of aviation soot, (ii) the representation of vertical updrafts in the model, and (iii) the use of reanalysis data to relax the model dynamics (the so-called nudging technique). Based on the results of the model simulations, a radiative forcing from the aviation soot–cirrus effect in the range of −35 to 13 mW m −2 is quantified, depending on the assumed critical saturation ratio for ice nucleation and active fraction of aviation soot but with a confidence level below 95 % in several cases. Simple idealized experiments with prescribed vertical velocities further show that the uncertainties on this aspect of the model dynamics are critical for the investigated effect and could potentially add a factor of about 2 of further uncertainty to the model estimates of the resulting radiative forcing. The use of the nudging technique to relax model dynamics is proved essential in order to identify a statistically significant signal from the model internal variability, while simulations performed in free-running mode and with prescribed sea-surface temperatures and sea-ice concentrations are shown to be unable to provide robust estimates of the investigated effect. A comparison with analogous model studies on the aviation soot–cirrus effect show a very large model diversity, with a conspicuous lack of consensus across the various estimates, which points to the need for more in-depth analyses on the roots of such discrepancies. |
format |
Text |
author |
Righi, Mattia Hendricks, Johannes Beer, Christof Gerhard |
spellingShingle |
Righi, Mattia Hendricks, Johannes Beer, Christof Gerhard Exploring the uncertainties in the aviation soot–cirrus effect |
author_facet |
Righi, Mattia Hendricks, Johannes Beer, Christof Gerhard |
author_sort |
Righi, Mattia |
title |
Exploring the uncertainties in the aviation soot–cirrus effect |
title_short |
Exploring the uncertainties in the aviation soot–cirrus effect |
title_full |
Exploring the uncertainties in the aviation soot–cirrus effect |
title_fullStr |
Exploring the uncertainties in the aviation soot–cirrus effect |
title_full_unstemmed |
Exploring the uncertainties in the aviation soot–cirrus effect |
title_sort |
exploring the uncertainties in the aviation soot–cirrus effect |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-17267-2021 https://acp.copernicus.org/articles/21/17267/2021/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-21-17267-2021 https://acp.copernicus.org/articles/21/17267/2021/ |
op_doi |
https://doi.org/10.5194/acp-21-17267-2021 |
container_title |
Atmospheric Chemistry and Physics |
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21 |
container_issue |
23 |
container_start_page |
17267 |
op_container_end_page |
17289 |
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1766195485720182784 |