DOI: 10.1016/j.atmosenv.2015.06.029
Scopus记录号: 2-s2.0-84936763220
论文题名: Global aerosol mixtures and their multiyear and seasonal characteristics
作者: Taylor M ; , Kazadzis S ; , Amiridis V ; , Kahn R ; A
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2015
卷: 116 起始页码: 112
结束页码: 129
语种: 英语
英文关键词: AERONET
; Atmospheric aerosol
; Classification
; Cluster analysis
; GOCART
Scopus关键词: Aerosols
; Atmospheric aerosols
; Chemical analysis
; Classification (of information)
; Cluster analysis
; Dust
; Mixtures
; Parameter estimation
; Site selection
; Uncertainty analysis
; AERONET
; Aerosol robotic networks
; GOCART
; Law of diminishing returns
; Microphysical parameters
; Seasonal characteristics
; Single scattering albedo
; Upper and lower bounds
; Atmospheric movements
; sulfate
; AERONET
; aerosol
; algorithm
; biomass burning
; climate forcing
; cluster analysis
; dust
; global change
; optical depth
; sea salt
; seasonal variation
; spatial distribution
; sulfate
; timescale
; wavelength
; aerosol
; Article
; atmosphere
; biomass
; cluster analysis
; controlled study
; optical depth
; priority journal
; season
; simulation
; taxonomy
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: The optical and microphysical characteristics of distinct aerosol types in the atmosphere are not yet specified at the level of detail required for climate forcing studies. What is even less well known are the characteristics of mixtures of aerosol and, in particular, their precise global spatial distribution. Here, cluster analysis is applied to seven years of 3-hourly, gridded 2.5°×2° aerosol optical depth data from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, one of the most-studied global simulations of aerosol type currently available, to construct a spatial partition of the globe into a finite number of aerosol mixtures. The optimal number of aerosol mixtures is obtained with a k-means algorithm with smart seeding in conjunction with a stopping condition based on applying the 'law of diminishing returns' to the norm of the Euclidean distance to provide upper and lower bounds on the number of clusters. Each cluster has a distinct composition in terms of the proportion of biomass burning, sulfate, dust and marine (sea salt) aerosol and this leads rather naturally to a taxonomy for labeling aerosol mixtures. In addition, the assignment of primary colors to constituent aerosol types enables true color-mixing and the production of easy-to-interpret maps of their distribution. The mean multiyear global partition as well as partitions deduced on the seasonal timescale are used to extract aerosol robotic network (AERONET) Level 2.0 Version 2 inversion products in each cluster for estimating the values of key optical and microphysical parameters to help characterize aerosol mixtures. On the multiyear timescale, the globe can be spatially partitioned into 10 distinct aerosol mixtures, with only marginally more variability on the seasonal timescale. In the context of the observational constraints and uncertainties associated with AERONET retrievals, bivariate analysis suggests that mixtures dominated by dust and marine aerosol can be detected with reference to their single scattering albedo and Angstrom exponent at visible wavelengths in conjunction with their fine mode fraction and sphericity. Existing multivariate approaches at classification appear to be more ambiguous. The approach presented here provides gridded (1°×1°) mean compositions of aeorosol mixtures as well as tentative estimates of mean aerosol optical and microphysical parameters in planetary regions where AERONET sites do not yet exist. Spreadsheets of gridded cluster indices for multiyear and seasonal partitions are provided to facililate further study of the global distribution of aerosol mixtures and possibly for the selection of new AERONET site locations. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/81604
Appears in Collections: 气候变化事实与影响
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作者单位: Institute for Environmental Research and Sustainable Development (IERSD), National Observatory of Athens (NOA), Metaxa and Vas Pavlou, Penteli, Athens, Greece; Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center (PMOD/WRC), Dorfstrasse 33, Davos Dorf, Switzerland; Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), National Observatory of Athens (NOA), Metaxa and Vas Pavlou, Penteli, Athens, Greece; NASA Goddard Space Flight Centre (GSFC), Greenbelt, MD, United States
Recommended Citation:
Taylor M,, Kazadzis S,, Amiridis V,et al. Global aerosol mixtures and their multiyear and seasonal characteristics[J]. Atmospheric Environment,2015-01-01,116