Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.5194/acp-18-3817-2018 |
Aircraft and ground measurements of dust aerosols over the west African coast in summer 2015 during ICE-D and AER-D | |
Liu, Dantong1; Taylor, JonathanW.1; Crosier, Jonathan1; Marsden, Nicholas1; Bower, Keith N.1; Lloyd, Gary1; Ryder, Claire L.2; Brooke, Jennifer K.3; Cotton, Richard3; Marenco, Franco3; Blyth, Alan4; Cui, Zhiqiang4; Estelles, Victor5; Gallagher, Martin1; Coe, Hugh1; Choularton, Tom W.1 | |
2018-03-16 | |
发表期刊 | ATMOSPHERIC CHEMISTRY AND PHYSICS
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ISSN | 1680-7316 |
EISSN | 1680-7324 |
出版年 | 2018 |
卷号 | 18期号:5页码:3817-3838 |
文章类型 | Article |
语种 | 英语 |
国家 | England; Spain |
英文摘要 | During the summertime, dust from the Sahara can be efficiently transported westwards within the Saharan air layer (SAL). This can lead to high aerosol loadings being observed above a relatively clean marine boundary layer (MBL) in the tropical Atlantic Ocean. These dust layers can impart significant radiative effects through strong visible and IR light absorption and scattering, and can also have indirect impacts by altering cloud properties. The processing of the dust aerosol can result in changes in both direct and indirect radiative effects, leading to significant uncertainty in climate prediction in this region. During August 2015, measurements of aerosol and cloud properties were conducted off the coast of west Africa as part of the Ice in Cloud Experiment - Dust (ICE-D) and AERosol properties - Dust (AER-D) campaigns. Observations were obtained over a 4-week period using the UK Facility for Atmospheric Airborne Measurements (FAAM) BAe 146 aircraft based on Santiago Island, Cabo Verde. Ground-based observations were collected from Praia (14 degrees 57' N, 23 degrees 29' W; 100 m a.s.l.), also located on Santiago Island. The dust in the SAL was mostly sampled in situ at altitudes of 2-4 km, and the potential dust age was estimated by backward trajectory analysis. The particle mass concentration (at diameter d = 0.1-20 mu m) decreased with transport time. Mean effective diameter (D-eff) for supermicron SAL dust (d = 1-20 mu m) was found to be 5-6 mu m regardless of dust age, whereas submicron D-eff (d = 0.1-1 mu m) showed a decreasing trend with longer transport. For the first time, an airborne laser-induced incandescence instrument (the single particle soot photometer - SP2) was deployed to measure the hematite content of dust. For the Sahel-influenced dust in the SAL, the observed hematite mass fraction of dust (F-Hm) was found to be anti-correlated with the single scattering albedo (SSA, lambda = 550 nm, for particles d < 2.5 mu m); as potential dust age increased from 2 to 7 days, F-Hm increased from 2.5 to 4.5 %, SSA decreased from 0.97 to 0.93 and the derived imaginary part (k) of the refractive index at 550 nm increased from 0.0015 to 0.0035. However, the optical properties of Sahara-influenced plumes (not influenced by the Sahel) were independent of dust age and hematite content with SSA similar to 0.95 and k similar to 0.0028. This indicates that the absorbing component of dust may be source dependent, or that gravitational settling of larger particles may lead to a higher fraction of more absorbing clay-iron aggregates at smaller sizes. Mie calculation using the measured size distribution and size-resolved refractive indices of the absorbing components (black carbon and hematite) reproduces the measured SSA to within +/- 0.02 for SAL dust by assuming a goethite / hematite mass ratio of 2. Overall, hematite and goethite constituted 40-80% of the absorption for particles d < 2.5 mu m, and black carbon (BC) contributed 10-37 %. This highlights the importance of size-dependent composition in determining the optical properties of dust and also the contribution from BC within dust plumes. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000427838400001 |
WOS关键词 | SAHARAN-MINERAL-DUST ; COMPLEX REFRACTIVE-INDEX ; OPTICAL-PROPERTIES ; BOUNDARY-LAYER ; BLACK-CARBON ; CHEMICAL-COMPOSITION ; MASS-SPECTROMETER ; SIZE DISTRIBUTION ; MIXING STATE ; CAPE-VERDE |
WOS类目 | Environmental Sciences ; Meteorology & Atmospheric Sciences |
WOS研究方向 | Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/16134 |
专题 | 地球科学 |
作者单位 | 1.Univ Manchester, Sch Earth & Environm Sci, Ctr Atmospher Sci, Manchester, Lancs, England; 2.Univ Reading, Dept Meteorol, Reading, Berks, England; 3.Met Off, Exeter, Devon, England; 4.Univ Leeds, Sch Earth & Environm, Leeds, W Yorkshire, England; 5.Univ Valencia, Dept Fis Terra & Termodinam, C Dr Moliner 50, Burjassot, Spain |
推荐引用方式 GB/T 7714 | Liu, Dantong,Taylor, JonathanW.,Crosier, Jonathan,et al. Aircraft and ground measurements of dust aerosols over the west African coast in summer 2015 during ICE-D and AER-D[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2018,18(5):3817-3838. |
APA | Liu, Dantong.,Taylor, JonathanW..,Crosier, Jonathan.,Marsden, Nicholas.,Bower, Keith N..,...&Choularton, Tom W..(2018).Aircraft and ground measurements of dust aerosols over the west African coast in summer 2015 during ICE-D and AER-D.ATMOSPHERIC CHEMISTRY AND PHYSICS,18(5),3817-3838. |
MLA | Liu, Dantong,et al."Aircraft and ground measurements of dust aerosols over the west African coast in summer 2015 during ICE-D and AER-D".ATMOSPHERIC CHEMISTRY AND PHYSICS 18.5(2018):3817-3838. |
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