Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties
Freshly emitted soot particles are fractal-like aggregates, but atmospheric processes often transform their morphology. Morphology of soot particles plays an important role in determining their optical properties, life cycle and hence their effect on Earth’s radiative balance. However, little is kno...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2015-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/10/11/114010 |
| _version_ | 1797748646670761984 |
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| author | Swarup China Gourihar Kulkarni Barbara V Scarnato Noopur Sharma Mikhail Pekour John E Shilling Jacqueline Wilson Alla Zelenyuk Duli Chand Shang Liu Allison C Aiken Manvendra Dubey Alexander Laskin Rahul A Zaveri Claudio Mazzoleni |
| author_facet | Swarup China Gourihar Kulkarni Barbara V Scarnato Noopur Sharma Mikhail Pekour John E Shilling Jacqueline Wilson Alla Zelenyuk Duli Chand Shang Liu Allison C Aiken Manvendra Dubey Alexander Laskin Rahul A Zaveri Claudio Mazzoleni |
| author_sort | Swarup China |
| collection | DOAJ |
| description | Freshly emitted soot particles are fractal-like aggregates, but atmospheric processes often transform their morphology. Morphology of soot particles plays an important role in determining their optical properties, life cycle and hence their effect on Earth’s radiative balance. However, little is known about the morphology of soot particles that participated in cold cloud processes. Here we report results from laboratory experiments that simulate cold cloud processing of diesel soot particles by allowing them to form supercooled droplets and ice crystals at −20 and −40 °C, respectively. Electron microscopy revealed that soot residuals from ice crystals were more compact (roundness ∼0.55) than those from supercooled droplets (roundness ∼0.45), while nascent soot particles were the least compact (roundness ∼0.41). Optical simulations using the discrete dipole approximation showed that the more compact structure enhances soot single scattering albedo by a factor up to 1.4, thereby reducing the top-of-the-atmosphere direct radiative forcing by ∼63%. These results underscore that climate models should consider the morphological evolution of soot particles due to cold cloud processing to improve the estimate of direct radiative forcing of soot. |
| first_indexed | 2024-03-12T16:07:46Z |
| format | Article |
| id | doaj.art-a748c42304b04c63a4369bac6eb2a7d3 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:07:46Z |
| publishDate | 2015-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-a748c42304b04c63a4369bac6eb2a7d32023-08-09T14:17:00ZengIOP PublishingEnvironmental Research Letters1748-93262015-01-01101111401010.1088/1748-9326/10/11/114010Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical propertiesSwarup China0Gourihar Kulkarni1Barbara V Scarnato2Noopur Sharma3Mikhail Pekour4John E Shilling5Jacqueline Wilson6Alla Zelenyuk7Duli Chand8Shang Liu9Allison C Aiken10Manvendra Dubey11Alexander Laskin12Rahul A Zaveri13Claudio Mazzoleni14Atmospheric Sciences Program and Physics Department, Michigan Technological University , Houghton MI, USA; Now at: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA, USAAtmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA, USADepartment of Meteorology, Naval Postgraduate School, Monterey CA, USAAtmospheric Sciences Program and Physics Department, Michigan Technological University , Houghton MI, USAAtmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA, USAAtmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA, USAChemical Physics and Analysis, Pacific Northwest National Laboratory, Richland WA, USAChemical Physics and Analysis, Pacific Northwest National Laboratory, Richland WA, USAAtmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA, USAEarth and Environmental Sciences Division, Los Alamos National laboratory, Los Alamos NM, USA; Now at: Cooperative Institute for Research in Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado , Boulder CO, USAEarth and Environmental Sciences Division, Los Alamos National laboratory, Los Alamos NM, USAEarth and Environmental Sciences Division, Los Alamos National laboratory, Los Alamos NM, USAEnvironmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA, USAAtmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA, USAAtmospheric Sciences Program and Physics Department, Michigan Technological University , Houghton MI, USAFreshly emitted soot particles are fractal-like aggregates, but atmospheric processes often transform their morphology. Morphology of soot particles plays an important role in determining their optical properties, life cycle and hence their effect on Earth’s radiative balance. However, little is known about the morphology of soot particles that participated in cold cloud processes. Here we report results from laboratory experiments that simulate cold cloud processing of diesel soot particles by allowing them to form supercooled droplets and ice crystals at −20 and −40 °C, respectively. Electron microscopy revealed that soot residuals from ice crystals were more compact (roundness ∼0.55) than those from supercooled droplets (roundness ∼0.45), while nascent soot particles were the least compact (roundness ∼0.41). Optical simulations using the discrete dipole approximation showed that the more compact structure enhances soot single scattering albedo by a factor up to 1.4, thereby reducing the top-of-the-atmosphere direct radiative forcing by ∼63%. These results underscore that climate models should consider the morphological evolution of soot particles due to cold cloud processing to improve the estimate of direct radiative forcing of soot.https://doi.org/10.1088/1748-9326/10/11/114010sootmorphologyice cloud processingoptical propertiesradiative forcing |
| spellingShingle | Swarup China Gourihar Kulkarni Barbara V Scarnato Noopur Sharma Mikhail Pekour John E Shilling Jacqueline Wilson Alla Zelenyuk Duli Chand Shang Liu Allison C Aiken Manvendra Dubey Alexander Laskin Rahul A Zaveri Claudio Mazzoleni Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties Environmental Research Letters soot morphology ice cloud processing optical properties radiative forcing |
| title | Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties |
| title_full | Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties |
| title_fullStr | Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties |
| title_full_unstemmed | Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties |
| title_short | Morphology of diesel soot residuals from supercooled water droplets and ice crystals: implications for optical properties |
| title_sort | morphology of diesel soot residuals from supercooled water droplets and ice crystals implications for optical properties |
| topic | soot morphology ice cloud processing optical properties radiative forcing |
| url | https://doi.org/10.1088/1748-9326/10/11/114010 |
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