Global impacts of organic aerosol acidity on sulfate and cloud formation
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866911190845751296 |
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| author | Sengupta, Gargi Ghosh, Kunal Jallu, Prithvi R. Prisle, Nønne L. |
| author_facet | Sengupta, Gargi Ghosh, Kunal Jallu, Prithvi R. Prisle, Nønne L. |
| contents | Organic aerosols (OA) comprise a major fraction of atmospheric particulate matter and frequently contain acidic species, yet their contribution to overall aerosol acidity has not been explicitly considered in global climate models. We implement concentration-dependent OA acid dissociation, including recently demonstrated surface-specific effects, into the ECHAM-HAMMOZ global climate model and assess the impacts on aqueous aerosol sulfate chemistry and aerosol--cloud--climate interactions. We show that enhanced aerosol acidity from OA acid dissociation drives increased sulfate formation from aqueous-phase oxidation of $\mathrm{SO_2}$. The microphysics of additional secondary sulfate aerosol changes global cloud droplet number concentrations (CDNC), with enhancements up to $13.9\%$. Increased cloud formation leads to a significant global mean cooling effect with a shortwave cloud radiative forcing (SWCRF) up to $-0.97~\mathrm{W\,m^{-2}}$. We also find that surface-specific acid dissociation effects can further modify both aerosol chemistry and resulting aerosol--cloud--climate responses, in some cases with even stronger impact than bulk acidity conditions. Our results demonstrate significant effects of considering OA acidity, as well as surface-specific phenomena, in global climate models. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_03030 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Global impacts of organic aerosol acidity on sulfate and cloud formation Sengupta, Gargi Ghosh, Kunal Jallu, Prithvi R. Prisle, Nønne L. Atmospheric and Oceanic Physics Organic aerosols (OA) comprise a major fraction of atmospheric particulate matter and frequently contain acidic species, yet their contribution to overall aerosol acidity has not been explicitly considered in global climate models. We implement concentration-dependent OA acid dissociation, including recently demonstrated surface-specific effects, into the ECHAM-HAMMOZ global climate model and assess the impacts on aqueous aerosol sulfate chemistry and aerosol--cloud--climate interactions. We show that enhanced aerosol acidity from OA acid dissociation drives increased sulfate formation from aqueous-phase oxidation of $\mathrm{SO_2}$. The microphysics of additional secondary sulfate aerosol changes global cloud droplet number concentrations (CDNC), with enhancements up to $13.9\%$. Increased cloud formation leads to a significant global mean cooling effect with a shortwave cloud radiative forcing (SWCRF) up to $-0.97~\mathrm{W\,m^{-2}}$. We also find that surface-specific acid dissociation effects can further modify both aerosol chemistry and resulting aerosol--cloud--climate responses, in some cases with even stronger impact than bulk acidity conditions. Our results demonstrate significant effects of considering OA acidity, as well as surface-specific phenomena, in global climate models. |
| title | Global impacts of organic aerosol acidity on sulfate and cloud formation |
| topic | Atmospheric and Oceanic Physics |
| url | https://arxiv.org/abs/2510.03030 |