DOI: 10.1002/2013JD021255
论文题名: Quantifying particle size and turbulent scale dependence of dust flux in the Sahara using aircraft measurements
作者: Rosenberg P.D. ; Parker D.J. ; Ryder C.L. ; Marsham J.H. ; Garcia-Carreras L. ; Dorsey J.R. ; Brooks I.M. ; Dean A.R. ; Crosier J. ; McQuaid J.B. ; Washington R.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 21698996
出版年: 2014
卷: 119, 期: 12 起始页码: 7577
结束页码: 7598
语种: 英语
英文关键词: aircraft measurements
; eddy covariance flux
; emission
; mineral dust
; subgrid parameterization
; topography
Scopus关键词: Aircraft
; Arid regions
; Atmospheric movements
; Atmospheric thermodynamics
; Dust
; Kinetic energy
; Kinetics
; Neutron emission
; Topography
; Aircraft measurement
; Eddy covariance
; High frequency measurements
; Mineral dust
; Particle drift velocity
; Subgrid parameterization
; Topographical variations
; Turbulent kinetic energy
; Particle size
英文摘要: The first size-resolved airborne measurements of dust fluxes and the first dust flux measurements from the central Sahara are presented and compared with a parameterization by Kok (2011a). High-frequency measurements of dust size distribution were obtained from 0.16 to 300 μm diameter, and eddy covariance fluxes were derived. This is more than an order of magnitude larger size range than previous flux estimates. Links to surface emission are provided by analysis of particle drift velocities. Number flux is described by a -2 power law between 1 and 144 μm diameter, significantly larger than the 12 μm upper limit suggested by Kok (2011a). For small particles, the deviation from a power law varies with terrain type and the large size cutoff is correlated with atmospheric vertical turbulent kinetic energy, suggesting control by vertical transport rather than emission processes. The measured mass flux mode is in the range 30-100 μm. The turbulent scales important for dust flux are from 0.1 km to 1-10 km. The upper scale increases during the morning as boundary layer depth and eddy size increase. All locations where large dust fluxes were measured had large topographical variations. These features are often linked with highly erodible surface features, such as wadis or dunes. We also hypothesize that upslope flow and flow separation over such features enhance the dust flux by transporting large particles out of the saltation layer. The tendency to locate surface flux measurements in open, flat terrain means these favored dust sources have been neglected in previous studies. Key Points Aircraft based, size-resolved, Saharan dust fluxes are measured The eddy covariance method is used with particles up to 300 micrometers Links to terrain, topography and vertical turbulent kinetic energy are discussed ©2014. American Geophysical Union. All Rights Reserved. 资助项目: NE/G017166/1
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63053
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: Institute of Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Met Office, Exeter, United Kingdom; Department of Meteorology, University of Reading, Reading, United Kingdom; Department of Meteorology, Bert Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden; National Centre for Atmospheric Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, United Kingdom; Facility for Airborne Atmospheric Measurements, Cranfield, United Kingdom; Climate Research Lab, Oxford University Centre for the Environment, Oxford, United Kingdom
Recommended Citation:
Rosenberg P.D.,Parker D.J.,Ryder C.L.,et al. Quantifying particle size and turbulent scale dependence of dust flux in the Sahara using aircraft measurements[J]. Journal of Geophysical Research: Atmospheres,2014-01-01,119(12)