DOI: 10.1002/2013JD020342
论文题名: Evidence of a weakly absorbing intermediate mode of aerosols in AERONET data from Saharan and Sahelian sites
作者: Gianelli S.M. ; Lacis A.A. ; Carlson B.E. ; Hameed S.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 22 起始页码: 12661
结束页码: 12672
语种: 英语
英文关键词: AERONET
; aerosols
; Saharan dust
; size distribution
Scopus关键词: Deconvolution
; Dust
; Size distribution
; Solar radiation
; Storms
; AERONET
; Aerosol robotic networks
; Aerosol size distributions
; Bimodal distribution
; Biomass-burning
; Saharan dust
; Single-scattering albedo
; Spectral deconvolution
; Aerosols
; albedo
; algorithm
; biomass burning
; data set
; deconvolution
; dust
; health impact
; optical depth
; particle size
; size distribution
; Canary Islands
; Cape Verde [Macaronesia]
; Sahara
; Sahel [Sub-Saharan Africa]
; Spain
英文摘要: Accurate retrievals of aerosol size distribution are necessary to estimate aerosols' impact on climate and human health. The inversions of the Aerosol Robotic Network (AERONET) usually retrieve bimodal distributions. However, when the inversion is applied to Saharan and Sahelian dust, an additional mode of intermediate size between the coarse and fine modes is sometimes seen. This mode explains peculiarities in the behavior of the Ångström exponent, along with the fine mode fraction retrieved using the spectral deconvolution algorithm, observed in a March 2006 dust storm. For this study, 15 AERONET sites in northern Africa and on the Atlantic are examined to determine the frequency and properties of the intermediate mode. The mode is observed most frequently at Ilorin in Nigeria. It is also observed at Capo Verde and multiple sites located within the Sahel but much less frequently at sites in the northern Sahara and the Canary Islands. The presence of the intermediate mode coincides with increases in Ångström exponent, fine mode fraction, single-scattering albedo, and to a lesser extent percent sphericity. The Ångström exponent decreases with increasing optical depth at most sites when the intermediate mode is present, but the fine mode fraction does not. Single-scattering albedo does not steadily decrease with fine mode fraction when the intermediate mode is present, as it does in typical mixtures of dust and biomass-burning aerosols. Continued investigation is needed to further define the intermediate mode's properties, determine why it differs from most Saharan dust, and identify its climate and health effects. Key Points AERONET inversions of Saharan dust sometimes show an intermediate size mode These retrievals explain what is observed in the direct beam data The mode appears to absorb sunlight less strongly than regular desert dust ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63137
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11790, United States; Department of Physical Sciences, St. Joseph's College, Patchogue, NY, United States; Department of Physics and Astronomy, Hofstra University, Hempstead, NY, United States; NASA Goddard Institute for Space Studies, New York, NY, United States
Recommended Citation:
Gianelli S.M.,Lacis A.A.,Carlson B.E.,et al. Evidence of a weakly absorbing intermediate mode of aerosols in AERONET data from Saharan and Sahelian sites[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(22)