气候变化领域集成服务门户(CCPortal): Classification of aerosol population type and cloud condensation nuclei properties in a coastal California littoral environment using an unsupervised cluster model

CCPortal

DOI	10.5194/acp-19-6931-2019
	Classification of aerosol population type and cloud condensation nuclei properties in a coastal California littoral environment using an unsupervised cluster model
	Atwood S.A.; Kreidenweis S.M.; Demott P.J.; Petters M.D.; Cornwell G.C.; Martin A.C.; Moore K.A.
发表日期	2019
ISSN	16807316
起始页码	6931
结束页码	6947
卷号	19 期号:10
英文摘要	Aerosol particle and cloud condensation nuclei (CCN) measurements from a littoral location on the northern coast of California at Bodega Bay Marine Laboratory (BML) are presented for approximately six weeks of observations during the boreal winter-spring as part of the CalWater-2015 field campaign. The nature and variability of surface (marine boundary layer, MBL) aerosol populations were evaluated by classifying observations into periods of similar aerosol and meteorological characteristics using an unsupervised cluster model to derive distinct littoral aerosol population types and link them to source regions. Such classifications support efforts to understand the impact of changing aerosol properties on precipitation and cloud development in the region, including during important atmospheric river (AR) tropical moisture advection events. Eight aerosol population types were identified that were associated with a range of impacts from both marine and terrestrial sources. Average measured total particle number concentrations, size distributions, hygroscopicities, and activated fraction spectra between 0.08 % and 1.1 % supersaturation are given for each of the identified aerosol population types, along with meteorological observations and transport pathways during time periods associated with each type. Five terrestrially influenced aerosol population types represented different degrees of aging of the continental outflow from the coast and interior of California, and their appearance at the BML site was often linked to changes in wind direction and transport pathways. In particular, distinct aerosol populations, associated with diurnal variations in source regions induced by land-and sea-breeze shifts, were classified by the clustering technique. A terrestrial type representing fresh emissions, and/or a recent new particle formation event, occurred in approximately 10% of the observations. Over the entire study period, three marine-influenced population types were identified that typically occurred when the regular diurnal land and sea-breeze cycle collapsed and BML was continuously ventilated by air masses from marine regions for multiple days. These marine types differed from each other primarily in the degree of cloud processing evident in the size distributions, and in the presence of an additional large-particle mode for the type associated with the highest wind speeds. One of the marine types was associated with a multi-day period during which an atmospheric river made landfall at BML. Differences between many of the terrestrial and marine population types in total CCN number concentrations active at a specific supersaturation were often not as pronounced as the associated differences in the corresponding activated fraction spectra, particularly for supersaturations below about 0.4%. This finding was due to the generally higher number concentrations in terrestrial air masses offsetting the lower fraction of particles activating at low supersaturations. At higher supersaturations, CCN concentrations for aged terrestrial types were typically above those of the marine types due to their higher number concentrations. © 2019 Author(s).
语种	英语
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/144383
作者单位	Department of Atmospheric Science, Colorado State University, Fort Collins, CO, United States; Department of Marine Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC, United States; Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA, United States; Climate Atmospheric Science and Physical Oceanography, Scripps Institution of Oceanography, San Diego, CA, United States; Department of Geography, Portland State University, Portland, OR, United States
推荐引用方式 GB/T 7714	Atwood S.A.,Kreidenweis S.M.,Demott P.J.,et al. Classification of aerosol population type and cloud condensation nuclei properties in a coastal California littoral environment using an unsupervised cluster model[J],2019,19(10).
APA	Atwood S.A..,Kreidenweis S.M..,Demott P.J..,Petters M.D..,Cornwell G.C..,...&Moore K.A..(2019).Classification of aerosol population type and cloud condensation nuclei properties in a coastal California littoral environment using an unsupervised cluster model.Atmospheric Chemistry and Physics,19(10).
MLA	Atwood S.A.,et al."Classification of aerosol population type and cloud condensation nuclei properties in a coastal California littoral environment using an unsupervised cluster model".Atmospheric Chemistry and Physics 19.10(2019).