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DOI	10.1016/j.atmosres.2020.105250
	The Saharan convective boundary layer structure over large scale surface heterogeneity: A large eddy simulation study
	Papangelis G.; Tombrou M.; Kalogiros J.
发表日期	2021
ISSN	0169-8095
卷号	248
英文摘要	Extreme atmospheric and surface conditions over the vast Saharan desert result in the development of one of the deepest atmospheric boundary layers (Saharan Atmospheric Boundary Layer, SABL) on the planet. The land cover in the Sahara mainly consists of wide interchanging areas of stony and sandy desert intercepted by narrower bare rock formations. Significant changes in surface albedo, surface temperature, turbulence fluxes and wind speed have been observed with remote measurement platforms like aircraft and satellites. This was a motivation to simulate the convective boundary layer (CBL) that develops over the heterogeneous Saharan surface with a two-way coupled system of a large eddy simulation code (LES) and a land surface model (LSM). Initial and boundary conditions are provided by airborne observations and mesoscale atmospheric simulations. In order to investigate the effect of surface heterogeneity on the vertical structure of the SABL, a large scale (larger than 10 km) idealized warm surface anomaly is simulated and analyzed. A land strip with a low surface albedo produces almost doubled fluxes in density and stronger convergence near the ground than over the surrounding brighter surfaces. First and second order turbulence statistics reveal that strong thermals penetrate the inversion layer above the CBL producing a vigorous exchange between unstable and overlying stable air. Furthermore, a convective internal boundary layer (CIBL) is formed over the warm strip. The downwind development of the CIBL is studied and CBL depth equations from literature are revised. The average turbulent structure of the SABL reveals flow changes locally and downwind of the surface heterogeneity (strip), which can be more significant than the dispersive fluxes due to surface heterogeneity, and may have an important effect on processes such as dust uplift and its long range transport that influence weather and climate globally. © 2020 Elsevier B.V.
语种	英语
scopus关键词	Atmospheric thermodynamics; Boundary layer flow; Large eddy simulation; Solar radiation; Surface properties; Turbulence; Wind; Airborne observations; Atmospheric simulations; Convective boundary layers; Initial and boundary conditions; Internal Boundary layer; Surface heterogeneities; Surface temperatures; Turbulence statistics; Atmospheric boundary layer; boundary layer; convective system; desert; heterogeneity; land cover; large eddy simulation; surface temperature; turbulence; wind velocity; Sahara; Satellites
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145225
作者单位	Department of Meteorology and Atmospheric Physics, University of Athens, Athens, Greece; Inst. of Env. Research & Sustainable Development, Nat. Observatory of Athens, Greece
推荐引用方式 GB/T 7714	Papangelis G.,Tombrou M.,Kalogiros J.. The Saharan convective boundary layer structure over large scale surface heterogeneity: A large eddy simulation study[J],2021,248.
APA	Papangelis G.,Tombrou M.,&Kalogiros J..(2021).The Saharan convective boundary layer structure over large scale surface heterogeneity: A large eddy simulation study.Atmospheric Research,248.
MLA	Papangelis G.,et al."The Saharan convective boundary layer structure over large scale surface heterogeneity: A large eddy simulation study".Atmospheric Research 248(2021).