A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer
We present a case study (20 September to 13 October 2015) of synergistic, multi-instrument observations of aerosols, clouds, and the marine boundary layer (MBL) at the Eastern North Atlantic (ENA) Atmospheric Radiation Measurement site centered on a period of exceptionally low (20–50 cm -3 ) surface...
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Online Access: | http://www.osti.gov/servlets/purl/1537321 https://www.osti.gov/biblio/1537321 https://doi.org/10.1002/2017jd027493 |
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ftosti:oai:osti.gov:1537321 2023-07-30T04:05:21+02:00 A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer Pennypacker, Sam Wood, Robert 2022-03-31 application/pdf http://www.osti.gov/servlets/purl/1537321 https://www.osti.gov/biblio/1537321 https://doi.org/10.1002/2017jd027493 unknown http://www.osti.gov/servlets/purl/1537321 https://www.osti.gov/biblio/1537321 https://doi.org/10.1002/2017jd027493 doi:10.1002/2017jd027493 54 ENVIRONMENTAL SCIENCES 2022 ftosti https://doi.org/10.1002/2017jd027493 2023-07-11T09:34:54Z We present a case study (20 September to 13 October 2015) of synergistic, multi-instrument observations of aerosols, clouds, and the marine boundary layer (MBL) at the Eastern North Atlantic (ENA) Atmospheric Radiation Measurement site centered on a period of exceptionally low (20–50 cm -3 ) surface accumulation mode (0.1–1 μm) aerosol particle number concentrations. We divide the case study into three regimes (high, clean, and ultraclean) based on daily median number concentrations and compare finer resolution (hourly or less) observations between these regimes. The analysis focuses on the possibility of using these ultraclean events to study pristine conditions in the remote MBL, as well as examining evidence for a recently proposed conceptual model for the large-scale depletion of cloud condensation nuclei-sized particles in postfrontal air masses. Relative to the high and clean regimes, the ultraclean regime tends to exhibit significantly fewer particles between 0.1 and 0.4 μm in diameter and a relatively increased prevalence of larger accumulation mode particles. In addition, supermicron particles tend to dominate total scattering in the ultraclean regime, and there is little evidence for absorbing aerosol. These observations are more in-line with a heavily scavenged but natural marine aerosol population and minimal contribution from continental sources such as anthropogenic pollution, biomass burning, or dust. The air masses with the consistently lowest accumulation mode aerosol number concentrations are largely dominated by heavily drizzling clouds with high liquid water path cores, deep decoupled boundary layers, open cellular organization, and notable surface forcing of subcloud turbulence, even at night. Other/Unknown Material North Atlantic SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Journal of Geophysical Research: Atmospheres 122 22 12,393 12,415 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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ftosti |
language |
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54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Pennypacker, Sam Wood, Robert A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
We present a case study (20 September to 13 October 2015) of synergistic, multi-instrument observations of aerosols, clouds, and the marine boundary layer (MBL) at the Eastern North Atlantic (ENA) Atmospheric Radiation Measurement site centered on a period of exceptionally low (20–50 cm -3 ) surface accumulation mode (0.1–1 μm) aerosol particle number concentrations. We divide the case study into three regimes (high, clean, and ultraclean) based on daily median number concentrations and compare finer resolution (hourly or less) observations between these regimes. The analysis focuses on the possibility of using these ultraclean events to study pristine conditions in the remote MBL, as well as examining evidence for a recently proposed conceptual model for the large-scale depletion of cloud condensation nuclei-sized particles in postfrontal air masses. Relative to the high and clean regimes, the ultraclean regime tends to exhibit significantly fewer particles between 0.1 and 0.4 μm in diameter and a relatively increased prevalence of larger accumulation mode particles. In addition, supermicron particles tend to dominate total scattering in the ultraclean regime, and there is little evidence for absorbing aerosol. These observations are more in-line with a heavily scavenged but natural marine aerosol population and minimal contribution from continental sources such as anthropogenic pollution, biomass burning, or dust. The air masses with the consistently lowest accumulation mode aerosol number concentrations are largely dominated by heavily drizzling clouds with high liquid water path cores, deep decoupled boundary layers, open cellular organization, and notable surface forcing of subcloud turbulence, even at night. |
author |
Pennypacker, Sam Wood, Robert |
author_facet |
Pennypacker, Sam Wood, Robert |
author_sort |
Pennypacker, Sam |
title |
A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer |
title_short |
A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer |
title_full |
A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer |
title_fullStr |
A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer |
title_full_unstemmed |
A Case Study in Low Aerosol Number Concentrations Over the Eastern North Atlantic: Implications for Pristine Conditions in the Remote Marine Boundary Layer |
title_sort |
case study in low aerosol number concentrations over the eastern north atlantic: implications for pristine conditions in the remote marine boundary layer |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1537321 https://www.osti.gov/biblio/1537321 https://doi.org/10.1002/2017jd027493 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://www.osti.gov/servlets/purl/1537321 https://www.osti.gov/biblio/1537321 https://doi.org/10.1002/2017jd027493 doi:10.1002/2017jd027493 |
op_doi |
https://doi.org/10.1002/2017jd027493 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
122 |
container_issue |
22 |
container_start_page |
12,393 |
op_container_end_page |
12,415 |
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1772817199342288896 |