Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model
Aerosol particles influence cloud formation and properties. Hence climate models that aim for a physical representation of the climate system include aerosol modules. In order to represent more and more processes and aerosol species, their representation has grown increasingly detailed. However, dep...
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ftdoajarticles:oai:doaj.org/article:8dd5ab71fbfb46c486d5b249b841206e 2024-09-15T18:37:18+00:00 Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model U. Proske S. Ferrachat U. Lohmann 2024-05-01T00:00:00Z https://doi.org/10.5194/acp-24-5907-2024 https://doaj.org/article/8dd5ab71fbfb46c486d5b249b841206e EN eng Copernicus Publications https://acp.copernicus.org/articles/24/5907/2024/acp-24-5907-2024.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-24-5907-2024 1680-7316 1680-7324 https://doaj.org/article/8dd5ab71fbfb46c486d5b249b841206e Atmospheric Chemistry and Physics, Vol 24, Pp 5907-5933 (2024) Physics QC1-999 Chemistry QD1-999 article 2024 ftdoajarticles https://doi.org/10.5194/acp-24-5907-2024 2024-08-05T17:49:21Z Aerosol particles influence cloud formation and properties. Hence climate models that aim for a physical representation of the climate system include aerosol modules. In order to represent more and more processes and aerosol species, their representation has grown increasingly detailed. However, depending on one's modelling purpose, the increased model complexity may not be beneficial, for example because it hinders understanding of model behaviour. Hence we develop a simplification in the form of a climatology of aerosol concentrations. In one approach, the climatology prescribes properties important for cloud droplet and ice crystal formation, the gateways for aerosols to enter the model cloud microphysics scheme. Another approach prescribes aerosol mass and number concentrations in general. Both climatologies are derived from full ECHAM-HAM simulations and can serve to replace the HAM aerosol module and thus drastically simplify the aerosol treatment. The first simplification reduces computational model time by roughly 65 %. However, the naive mean climatological treatment needs improvement to give results that are satisfyingly close to the full model. We find that mean cloud condensation nuclei (CCN) concentrations yield an underestimation of cloud droplet number concentration (CDNC) in the Southern Ocean, which we can reduce by allowing only CCN at cloud base (which have experienced hygroscopic growth in these conditions) to enter the climatology. This highlights the value of the simplification approach in pointing to unexpected model behaviour and providing a new perspective for its study and model development. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Atmospheric Chemistry and Physics 24 10 5907 5933 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 U. Proske S. Ferrachat U. Lohmann Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
Aerosol particles influence cloud formation and properties. Hence climate models that aim for a physical representation of the climate system include aerosol modules. In order to represent more and more processes and aerosol species, their representation has grown increasingly detailed. However, depending on one's modelling purpose, the increased model complexity may not be beneficial, for example because it hinders understanding of model behaviour. Hence we develop a simplification in the form of a climatology of aerosol concentrations. In one approach, the climatology prescribes properties important for cloud droplet and ice crystal formation, the gateways for aerosols to enter the model cloud microphysics scheme. Another approach prescribes aerosol mass and number concentrations in general. Both climatologies are derived from full ECHAM-HAM simulations and can serve to replace the HAM aerosol module and thus drastically simplify the aerosol treatment. The first simplification reduces computational model time by roughly 65 %. However, the naive mean climatological treatment needs improvement to give results that are satisfyingly close to the full model. We find that mean cloud condensation nuclei (CCN) concentrations yield an underestimation of cloud droplet number concentration (CDNC) in the Southern Ocean, which we can reduce by allowing only CCN at cloud base (which have experienced hygroscopic growth in these conditions) to enter the climatology. This highlights the value of the simplification approach in pointing to unexpected model behaviour and providing a new perspective for its study and model development. |
format |
Article in Journal/Newspaper |
author |
U. Proske S. Ferrachat U. Lohmann |
author_facet |
U. Proske S. Ferrachat U. Lohmann |
author_sort |
U. Proske |
title |
Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
title_short |
Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
title_full |
Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
title_fullStr |
Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
title_full_unstemmed |
Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
title_sort |
developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model |
publisher |
Copernicus Publications |
publishDate |
2024 |
url |
https://doi.org/10.5194/acp-24-5907-2024 https://doaj.org/article/8dd5ab71fbfb46c486d5b249b841206e |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Atmospheric Chemistry and Physics, Vol 24, Pp 5907-5933 (2024) |
op_relation |
https://acp.copernicus.org/articles/24/5907/2024/acp-24-5907-2024.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-24-5907-2024 1680-7316 1680-7324 https://doaj.org/article/8dd5ab71fbfb46c486d5b249b841206e |
op_doi |
https://doi.org/10.5194/acp-24-5907-2024 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
24 |
container_issue |
10 |
container_start_page |
5907 |
op_container_end_page |
5933 |
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1810481669560336384 |