Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC)
Abstract In recent years, researchers have emphasized the use of fractal aggregate morphology instead of the core-shell morphology in global climate models for estimating black carbon (BC) forcing. This study confirms that fractal morphology plays an important role in reducing the overestimation of...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2024-04-01
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| Series: | npj Climate and Atmospheric Science |
| Online Access: | https://doi.org/10.1038/s41612-024-00634-0 |
| _version_ | 1797209497992691712 |
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| author | Baseerat Romshoo Thomas Müller Ajit Ahlawat Alfred Wiedensohler M. V. Haneef Mohd. Imran Aisha Baig Warsi Anil Kumar Mandariya Gazala Habib Mira L. Pöhlker |
| author_facet | Baseerat Romshoo Thomas Müller Ajit Ahlawat Alfred Wiedensohler M. V. Haneef Mohd. Imran Aisha Baig Warsi Anil Kumar Mandariya Gazala Habib Mira L. Pöhlker |
| author_sort | Baseerat Romshoo |
| collection | DOAJ |
| description | Abstract In recent years, researchers have emphasized the use of fractal aggregate morphology instead of the core-shell morphology in global climate models for estimating black carbon (BC) forcing. This study confirms that fractal morphology plays an important role in reducing the overestimation of aerosol light absorption calculations in the case of an urban polluted environment. During periods of high anthropogenic BC emissions at Delhi, the particle light absorption is overestimated by 50 to 200% by assumptions of both external mixing and internal core-shell mixing. While incorporating the aggregate morphology model into light absorption simulations is beneficial in such cases, it comes with a high computational burden. To address this, we propose a metric known as morphology index (MI). This index distributes the weightage between the two extreme cases of core-shell and fractal aggregate to obtain accurate particle light absorption. Long-range transported aerosols were estimated to have an MI of 0.78, and fresh local emissions had an MI of 0.48. A BC-based aerosol classification approach was developed to determine the most relevant particle size mode for light absorption. The method is based on patterns found between the correlations of the BC mass concentrations and aerosol number concentrations at the different particles sizes (BC-size correlation spectra). BC-size correlation spectra are introduced as a concept that may be used (i) independently to understand the size-dependent heterogeneous distribution of aerosol light absorption and (ii) in conjunction with MI to accurately model the optical properties of aerosols in different BC regimes. |
| first_indexed | 2024-04-24T09:55:39Z |
| format | Article |
| id | doaj.art-b55e627560db4104afb71823f25bf799 |
| institution | Directory Open Access Journal |
| issn | 2397-3722 |
| language | English |
| last_indexed | 2024-04-24T09:55:39Z |
| publishDate | 2024-04-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Climate and Atmospheric Science |
| spelling | doaj.art-b55e627560db4104afb71823f25bf7992024-04-14T11:11:32ZengNature Portfolionpj Climate and Atmospheric Science2397-37222024-04-017111010.1038/s41612-024-00634-0Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC)Baseerat Romshoo0Thomas Müller1Ajit Ahlawat2Alfred Wiedensohler3M. V. Haneef4Mohd. Imran5Aisha Baig Warsi6Anil Kumar Mandariya7Gazala Habib8Mira L. Pöhlker9Leibniz Institute for Tropospheric ResearchLeibniz Institute for Tropospheric ResearchLeibniz Institute for Tropospheric ResearchLeibniz Institute for Tropospheric ResearchIndian Institute for Technology New Delhi (IIT-D)Indian Institute for Technology New Delhi (IIT-D)Indian Institute for Technology New Delhi (IIT-D)Univ Paris Est Creteil and Université Paris Cité, CNRS, LISAIndian Institute for Technology New Delhi (IIT-D)Leibniz Institute for Tropospheric ResearchAbstract In recent years, researchers have emphasized the use of fractal aggregate morphology instead of the core-shell morphology in global climate models for estimating black carbon (BC) forcing. This study confirms that fractal morphology plays an important role in reducing the overestimation of aerosol light absorption calculations in the case of an urban polluted environment. During periods of high anthropogenic BC emissions at Delhi, the particle light absorption is overestimated by 50 to 200% by assumptions of both external mixing and internal core-shell mixing. While incorporating the aggregate morphology model into light absorption simulations is beneficial in such cases, it comes with a high computational burden. To address this, we propose a metric known as morphology index (MI). This index distributes the weightage between the two extreme cases of core-shell and fractal aggregate to obtain accurate particle light absorption. Long-range transported aerosols were estimated to have an MI of 0.78, and fresh local emissions had an MI of 0.48. A BC-based aerosol classification approach was developed to determine the most relevant particle size mode for light absorption. The method is based on patterns found between the correlations of the BC mass concentrations and aerosol number concentrations at the different particles sizes (BC-size correlation spectra). BC-size correlation spectra are introduced as a concept that may be used (i) independently to understand the size-dependent heterogeneous distribution of aerosol light absorption and (ii) in conjunction with MI to accurately model the optical properties of aerosols in different BC regimes.https://doi.org/10.1038/s41612-024-00634-0 |
| spellingShingle | Baseerat Romshoo Thomas Müller Ajit Ahlawat Alfred Wiedensohler M. V. Haneef Mohd. Imran Aisha Baig Warsi Anil Kumar Mandariya Gazala Habib Mira L. Pöhlker Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC) npj Climate and Atmospheric Science |
| title | Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC) |
| title_full | Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC) |
| title_fullStr | Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC) |
| title_full_unstemmed | Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC) |
| title_short | Significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon (BC) |
| title_sort | significant contribution of fractal morphology to aerosol light absorption in polluted environments dominated by black carbon bc |
| url | https://doi.org/10.1038/s41612-024-00634-0 |
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