Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors
Cloud drop number concentrations (N d ) over the western North Atlantic Ocean (WNAO) are generally highest during the winter (DJF) and lowest in summer (JJA), in contrast to aerosol proxy variables (aerosoloptical depth, aerosol index, surface aerosol mass concentrations, surface cloud condensation...
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Online Access: | http://www.osti.gov/servlets/purl/1815700 https://www.osti.gov/biblio/1815700 https://doi.org/10.5194/acp-21-10499-2021 |
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ftosti:oai:osti.gov:1815700 2023-07-30T04:05:23+02:00 Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors Dadashazar, Hossein Painemal, David Alipanah, Majid Brunke, Michael Chellappan, Seethala Corral, Andrea F. Crosbie, Ewan Kirschler, Simon Liu, Hongyu Moore, Richard H. Robinson, Claire Scarino, Amy Jo Shook, Michael Sinclair, Kenneth Thornhill, K. Lee Voigt, Christiane Wang, Hailong Winstead, Edward Zeng, Xubin Ziemba, Luke Zuidema, Paquita Sorooshian, Armin 2021-11-01 application/pdf http://www.osti.gov/servlets/purl/1815700 https://www.osti.gov/biblio/1815700 https://doi.org/10.5194/acp-21-10499-2021 unknown http://www.osti.gov/servlets/purl/1815700 https://www.osti.gov/biblio/1815700 https://doi.org/10.5194/acp-21-10499-2021 doi:10.5194/acp-21-10499-2021 54 ENVIRONMENTAL SCIENCES 2021 ftosti https://doi.org/10.5194/acp-21-10499-2021 2023-07-11T10:06:25Z Cloud drop number concentrations (N d ) over the western North Atlantic Ocean (WNAO) are generally highest during the winter (DJF) and lowest in summer (JJA), in contrast to aerosol proxy variables (aerosoloptical depth, aerosol index, surface aerosol mass concentrations, surface cloud condensation nuclei (CCN) concentrations) that generally peak inspring (MAM) and JJA with minima in DJF. Using aircraft, satellite remote sensing, ground-based in situ measurement data, and reanalysis data, we characterize factors explaining the divergent seasonal cycles and furthermore probe into factors influencing N d on seasonal timescales. The results can be summarized well by features most pronounced in DJF, including features associated with cold-air outbreak (CAO) conditions such as enhanced values of CAO index, planetary boundary layer height (PBLH),low-level liquid cloud fraction, and cloud-top height, in addition to winds aligned with continental outflow. Data sorted into high- and low-N d days in each season, especially in DJF, revealed that all of these conditions were enhanced on the high-N d days, including reduced sea level pressure and stronger wind speeds. Although aerosols may be more abundant in MAM and JJA, the conditions needed to activate those particles into cloud droplets are weaker than in colder months, which is demonstrated by calculations of the strongest (weakest) aerosol indirect effects in DJF (JJA) based on comparing N d to perturbations in four different aerosol proxy variables (total and sulfate aerosol optical depth, aerosol index, surface mass concentration of sulfate). We used three machine learning models and up to 14 input variables to infer about most influential factors related to N d for DJF and JJA, with the best performance obtained with gradient-boosted regression tree (GBRT) analysis. The model results indicated that cloud fraction was the most important input variable, followed by some combination (depending on season) of CAO index and surface mass concentrations of sulfate and ... Other/Unknown Material North Atlantic SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Atmospheric Chemistry and Physics 21 13 10499 10526 |
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Open Polar |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Dadashazar, Hossein Painemal, David Alipanah, Majid Brunke, Michael Chellappan, Seethala Corral, Andrea F. Crosbie, Ewan Kirschler, Simon Liu, Hongyu Moore, Richard H. Robinson, Claire Scarino, Amy Jo Shook, Michael Sinclair, Kenneth Thornhill, K. Lee Voigt, Christiane Wang, Hailong Winstead, Edward Zeng, Xubin Ziemba, Luke Zuidema, Paquita Sorooshian, Armin Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Cloud drop number concentrations (N d ) over the western North Atlantic Ocean (WNAO) are generally highest during the winter (DJF) and lowest in summer (JJA), in contrast to aerosol proxy variables (aerosoloptical depth, aerosol index, surface aerosol mass concentrations, surface cloud condensation nuclei (CCN) concentrations) that generally peak inspring (MAM) and JJA with minima in DJF. Using aircraft, satellite remote sensing, ground-based in situ measurement data, and reanalysis data, we characterize factors explaining the divergent seasonal cycles and furthermore probe into factors influencing N d on seasonal timescales. The results can be summarized well by features most pronounced in DJF, including features associated with cold-air outbreak (CAO) conditions such as enhanced values of CAO index, planetary boundary layer height (PBLH),low-level liquid cloud fraction, and cloud-top height, in addition to winds aligned with continental outflow. Data sorted into high- and low-N d days in each season, especially in DJF, revealed that all of these conditions were enhanced on the high-N d days, including reduced sea level pressure and stronger wind speeds. Although aerosols may be more abundant in MAM and JJA, the conditions needed to activate those particles into cloud droplets are weaker than in colder months, which is demonstrated by calculations of the strongest (weakest) aerosol indirect effects in DJF (JJA) based on comparing N d to perturbations in four different aerosol proxy variables (total and sulfate aerosol optical depth, aerosol index, surface mass concentration of sulfate). We used three machine learning models and up to 14 input variables to infer about most influential factors related to N d for DJF and JJA, with the best performance obtained with gradient-boosted regression tree (GBRT) analysis. The model results indicated that cloud fraction was the most important input variable, followed by some combination (depending on season) of CAO index and surface mass concentrations of sulfate and ... |
author |
Dadashazar, Hossein Painemal, David Alipanah, Majid Brunke, Michael Chellappan, Seethala Corral, Andrea F. Crosbie, Ewan Kirschler, Simon Liu, Hongyu Moore, Richard H. Robinson, Claire Scarino, Amy Jo Shook, Michael Sinclair, Kenneth Thornhill, K. Lee Voigt, Christiane Wang, Hailong Winstead, Edward Zeng, Xubin Ziemba, Luke Zuidema, Paquita Sorooshian, Armin |
author_facet |
Dadashazar, Hossein Painemal, David Alipanah, Majid Brunke, Michael Chellappan, Seethala Corral, Andrea F. Crosbie, Ewan Kirschler, Simon Liu, Hongyu Moore, Richard H. Robinson, Claire Scarino, Amy Jo Shook, Michael Sinclair, Kenneth Thornhill, K. Lee Voigt, Christiane Wang, Hailong Winstead, Edward Zeng, Xubin Ziemba, Luke Zuidema, Paquita Sorooshian, Armin |
author_sort |
Dadashazar, Hossein |
title |
Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
title_short |
Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
title_full |
Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
title_fullStr |
Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
title_full_unstemmed |
Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
title_sort |
cloud drop number concentrations over the western north atlantic ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
publishDate |
2021 |
url |
http://www.osti.gov/servlets/purl/1815700 https://www.osti.gov/biblio/1815700 https://doi.org/10.5194/acp-21-10499-2021 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://www.osti.gov/servlets/purl/1815700 https://www.osti.gov/biblio/1815700 https://doi.org/10.5194/acp-21-10499-2021 doi:10.5194/acp-21-10499-2021 |
op_doi |
https://doi.org/10.5194/acp-21-10499-2021 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
21 |
container_issue |
13 |
container_start_page |
10499 |
op_container_end_page |
10526 |
_version_ |
1772817257481633792 |