气候变化领域集成服务门户(CCPortal): Gentle Topography Increases Vertical Transport of Coarse Dust by Orders of Magnitude

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DOI	10.1029/2021JD034564
	Gentle Topography Increases Vertical Transport of Coarse Dust by Orders of Magnitude
	Heisel M.; Chen B.; Kok J.F.; Chamecki M.
发表日期	2021
ISSN	2169-897X
卷号	126 期号:14
英文摘要	The presence of coarse mineral dust in the atmosphere has been substantiated in several recent measurement campaigns, which include observations of particles up to and above 100 μm in diameter. Yet, atmospheric dust models either do not include particles larger than 20 μm or severely underestimate their concentrations. One possibility for the underestimated concentrations is that models do not represent enhancements of particle transport due to subgrid-scale topography. Here, large-eddy simulations are used in combination with Lagrangian particle tracking to assess the impact of gentle two-dimensional topography with 50 and 100 m elevation on the vertical transport of coarse dust in neutrally stratified conditions. The presence of topography significantly increases the likelihood that 5 and 20 μm particles reach several hundred meters in altitude. Further, topography increases this likelihood by orders of magnitude for larger 60 μm particles. Three mechanisms are observed to contribute to the increased vertical transport: a strong upward mean flow region on the uphill side of the topography, ejection of particles downwind of the topography crest, and enhanced vertical dispersion in the wake of the crest. The compounding effects of these mechanisms provide a pathway for coarse dust emitted from the surface to reach elevations where they can be further transported into the free atmosphere by large-scale motions such as convective plumes. While these findings are motivated by mineral dust observations, they are generally applicable to other heavy aerosols such as pollen. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	coarse atmospheric dust; heavy particles; lagrangian tracking model; large eddy simulation; topography; turbulent transport
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/237134
作者单位	Department of Atmospheric & Oceanic Sciences, University of California in Los Angeles, Los Angeles, CA, United States; Department of Civil & Environmental Engineering, University of California in Berkeley, Berkeley, CA, United States
推荐引用方式 GB/T 7714	Heisel M.,Chen B.,Kok J.F.,et al. Gentle Topography Increases Vertical Transport of Coarse Dust by Orders of Magnitude[J],2021,126(14).
APA	Heisel M.,Chen B.,Kok J.F.,&Chamecki M..(2021).Gentle Topography Increases Vertical Transport of Coarse Dust by Orders of Magnitude.Journal of Geophysical Research: Atmospheres,126(14).
MLA	Heisel M.,et al."Gentle Topography Increases Vertical Transport of Coarse Dust by Orders of Magnitude".Journal of Geophysical Research: Atmospheres 126.14(2021).