气候变化领域集成服务门户(CCPortal): Cloud drop number concentrations over the western north atlantic ocean: Seasonal cycle, aerosol interrelationships, and other influential factors

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DOI	10.5194/acp-21-10499-2021
	Cloud drop number concentrations over the western north atlantic ocean: Seasonal cycle, aerosol interrelationships, and other influential factors
	Dadashazar H.; Painemal D.; Alipanah M.; Brunke M.; Chellappan S.; Corral A.F.; Crosbie E.; Kirschler S.; Liu H.; Moore R.H.; Robinson C.; Scarino A.J.; Shook M.; Sinclair K.; Thornhill K.L.; Voigt C.; Wang H.; Winstead E.; Zeng X.; Ziemba L.; Zuidema P.; Sorooshian A.
发表日期	2021
ISSN	1680-7316
起始页码	10499
结束页码	10526
卷号	21 期号:13
英文摘要	Cloud drop number concentrations (Nd) 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 Nd 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-Nd days in each season, especially in DJF, revealed that all of these conditions were enhanced on the high-Nd 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 Nd 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 Nd 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 organic carbon. Future work is recommended to further understand aspects uncovered here such as impacts of free tropospheric aerosol entrainment on clouds, degree of boundary layer coupling, wet scavenging, and giant CCN effects on aerosol-Nd relationships, updraft velocity, and vertical structure of cloud properties such as adiabaticity that impact the satellite estimation of Nd. © Copyright:
语种	英语
scopus关键词	aerosol; cloud condensation nucleus; concentration (composition); optical depth; seasonal variation; source apportionment; wind velocity; Atlantic Ocean; Atlantic Ocean (North)
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246739
作者单位	Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States; NASA Langley Research Center, Hampton, VA, United States; Science Systems and Applications Inc, Hampton, VA, United States; Department of Systems and Industrial Engineering, University of Arizona, Tucson, AZ, United States; Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United States; Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States; Institute of Atmospheric Physics, German Aerospace Center, Oberpfaffenhofen, Germany; National Institute of Aerospace, Hampton, VA, United States; NASA Goddard Institute for Space Studies, New York, NY, United States; Universities Space Research Association, Columbia, MD, United States; Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States
推荐引用方式 GB/T 7714	Dadashazar H.,Painemal D.,Alipanah M.,et al. Cloud drop number concentrations over the western north atlantic ocean: Seasonal cycle, aerosol interrelationships, and other influential factors[J],2021,21(13).
APA	Dadashazar H..,Painemal D..,Alipanah M..,Brunke M..,Chellappan S..,...&Sorooshian A..(2021).Cloud drop number concentrations over the western north atlantic ocean: Seasonal cycle, aerosol interrelationships, and other influential factors.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(13).
MLA	Dadashazar H.,et al."Cloud drop number concentrations over the western north atlantic ocean: Seasonal cycle, aerosol interrelationships, and other influential factors".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.13(2021).