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 (aerosol optical depth, aerosol index, surface aerosol mass concentrations, surface cloud condensatio...
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ftdoajarticles:oai:doaj.org/article:757a75bb06244fe9b95628be44e6df08 2023-05-15T17:32:02+02:00 Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors H. Dadashazar D. Painemal M. Alipanah M. Brunke S. Chellappan A. F. Corral E. Crosbie S. Kirschler H. Liu R. H. Moore C. Robinson A. J. Scarino M. Shook K. Sinclair K. L. Thornhill C. Voigt H. Wang E. Winstead X. Zeng L. Ziemba P. Zuidema A. Sorooshian 2021-07-01T00:00:00Z https://doi.org/10.5194/acp-21-10499-2021 https://doaj.org/article/757a75bb06244fe9b95628be44e6df08 EN eng Copernicus Publications https://acp.copernicus.org/articles/21/10499/2021/acp-21-10499-2021.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-21-10499-2021 1680-7316 1680-7324 https://doaj.org/article/757a75bb06244fe9b95628be44e6df08 Atmospheric Chemistry and Physics, Vol 21, Pp 10499-10526 (2021) Physics QC1-999 Chemistry QD1-999 article 2021 ftdoajarticles https://doi.org/10.5194/acp-21-10499-2021 2022-12-31T09:59:14Z 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 (aerosol optical depth, aerosol index, surface aerosol mass concentrations, surface cloud condensation nuclei (CCN) concentrations) that generally peak in spring (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 ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Atmospheric Chemistry and Physics 21 13 10499 10526 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 H. Dadashazar D. Painemal M. Alipanah M. Brunke S. Chellappan A. F. Corral E. Crosbie S. Kirschler H. Liu R. H. Moore C. Robinson A. J. Scarino M. Shook K. Sinclair K. L. Thornhill C. Voigt H. Wang E. Winstead X. Zeng L. Ziemba P. Zuidema A. Sorooshian Cloud drop number concentrations over the western North Atlantic Ocean: seasonal cycle, aerosol interrelationships, and other influential factors |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
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 (aerosol optical depth, aerosol index, surface aerosol mass concentrations, surface cloud condensation nuclei (CCN) concentrations) that generally peak in spring (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 ... |
format |
Article in Journal/Newspaper |
author |
H. Dadashazar D. Painemal M. Alipanah M. Brunke S. Chellappan A. F. Corral E. Crosbie S. Kirschler H. Liu R. H. Moore C. Robinson A. J. Scarino M. Shook K. Sinclair K. L. Thornhill C. Voigt H. Wang E. Winstead X. Zeng L. Ziemba P. Zuidema A. Sorooshian |
author_facet |
H. Dadashazar D. Painemal M. Alipanah M. Brunke S. Chellappan A. F. Corral E. Crosbie S. Kirschler H. Liu R. H. Moore C. Robinson A. J. Scarino M. Shook K. Sinclair K. L. Thornhill C. Voigt H. Wang E. Winstead X. Zeng L. Ziemba P. Zuidema A. Sorooshian |
author_sort |
H. Dadashazar |
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 |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-10499-2021 https://doaj.org/article/757a75bb06244fe9b95628be44e6df08 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Atmospheric Chemistry and Physics, Vol 21, Pp 10499-10526 (2021) |
op_relation |
https://acp.copernicus.org/articles/21/10499/2021/acp-21-10499-2021.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-21-10499-2021 1680-7316 1680-7324 https://doaj.org/article/757a75bb06244fe9b95628be44e6df08 |
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 |
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1766129959009517568 |