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A key process controlling the wet removal of aerosols: new observational evidence
The lifetime and spatial distributions of accumulation-mode aerosols in a size range of approximately 0.05–1 μm, and thus their global and regional climate impacts, are primarily constrained by their removal via cloud and precipitation (wet removal). However, the microphysical process that predomina...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5050421/ https://www.ncbi.nlm.nih.gov/pubmed/27703169 http://dx.doi.org/10.1038/srep34113 |
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author | Ohata, Sho Moteki, Nobuhiro Mori, Tatsuhiro Koike, Makoto Kondo, Yutaka |
author_facet | Ohata, Sho Moteki, Nobuhiro Mori, Tatsuhiro Koike, Makoto Kondo, Yutaka |
author_sort | Ohata, Sho |
collection | PubMed |
description | The lifetime and spatial distributions of accumulation-mode aerosols in a size range of approximately 0.05–1 μm, and thus their global and regional climate impacts, are primarily constrained by their removal via cloud and precipitation (wet removal). However, the microphysical process that predominantly controls the removal efficiency remains unidentified because of observational difficulties. Here, we demonstrate that the activation of aerosols to cloud droplets (nucleation scavenging) predominantly controls the wet removal efficiency of accumulation-mode aerosols, using water-insoluble black carbon as an observable particle tracer during the removal process. From simultaneous ground-based observations of black carbon in air (prior to removal) and in rainwater (after removal) in Tokyo, Japan, we found that the wet removal efficiency depends strongly on particle size, and the size dependence can be explained quantitatively by the observed size-dependent cloud-nucleating ability. Furthermore, our observational method provides an estimate of the effective supersaturation of water vapour in precipitating cloud clusters, a key parameter controlling nucleation scavenging. These novel data firmly indicate the importance of quantitative numerical simulations of the nucleation scavenging process to improve the model’s ability to predict the atmospheric aerosol burden and the resultant climate forcings, and enable a new validation of such simulations. |
format | Online Article Text |
id | pubmed-5050421 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-50504212016-10-11 A key process controlling the wet removal of aerosols: new observational evidence Ohata, Sho Moteki, Nobuhiro Mori, Tatsuhiro Koike, Makoto Kondo, Yutaka Sci Rep Article The lifetime and spatial distributions of accumulation-mode aerosols in a size range of approximately 0.05–1 μm, and thus their global and regional climate impacts, are primarily constrained by their removal via cloud and precipitation (wet removal). However, the microphysical process that predominantly controls the removal efficiency remains unidentified because of observational difficulties. Here, we demonstrate that the activation of aerosols to cloud droplets (nucleation scavenging) predominantly controls the wet removal efficiency of accumulation-mode aerosols, using water-insoluble black carbon as an observable particle tracer during the removal process. From simultaneous ground-based observations of black carbon in air (prior to removal) and in rainwater (after removal) in Tokyo, Japan, we found that the wet removal efficiency depends strongly on particle size, and the size dependence can be explained quantitatively by the observed size-dependent cloud-nucleating ability. Furthermore, our observational method provides an estimate of the effective supersaturation of water vapour in precipitating cloud clusters, a key parameter controlling nucleation scavenging. These novel data firmly indicate the importance of quantitative numerical simulations of the nucleation scavenging process to improve the model’s ability to predict the atmospheric aerosol burden and the resultant climate forcings, and enable a new validation of such simulations. Nature Publishing Group 2016-10-05 /pmc/articles/PMC5050421/ /pubmed/27703169 http://dx.doi.org/10.1038/srep34113 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
spellingShingle | Article Ohata, Sho Moteki, Nobuhiro Mori, Tatsuhiro Koike, Makoto Kondo, Yutaka A key process controlling the wet removal of aerosols: new observational evidence |
title | A key process controlling the wet removal of aerosols: new observational evidence |
title_full | A key process controlling the wet removal of aerosols: new observational evidence |
title_fullStr | A key process controlling the wet removal of aerosols: new observational evidence |
title_full_unstemmed | A key process controlling the wet removal of aerosols: new observational evidence |
title_short | A key process controlling the wet removal of aerosols: new observational evidence |
title_sort | key process controlling the wet removal of aerosols: new observational evidence |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5050421/ https://www.ncbi.nlm.nih.gov/pubmed/27703169 http://dx.doi.org/10.1038/srep34113 |
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