干旱区生态环境知识资源中心(Arid): Influence of Orography Upon Summertime Low-Level Jet Dust Emission in the Central and Western Sahara

Arid

DOI	10.1029/2021JD035025
	Influence of Orography Upon Summertime Low-Level Jet Dust Emission in the Central and Western Sahara
	Harrison, Thomas Caton; Washington, Richard; Engelstaedter, Sebastian; Jones, Richard G.; Savage, Nick H.
通讯作者	Harrison, TC (corresponding author), Univ Oxford, Ctr Environm, Climate Res Lab, Oxford, England. ; Harrison, TC (corresponding author), British Antarctic Survey, Cambridge, England.
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
ISSN	2169-897X
EISSN	2169-8996
出版年	2021
卷号	126 期号:23
英文摘要	Low-level jets (LLJs) drive frequent emission of mineral dust in the central and western Sahara in boreal summer. A major hotspot for this process is central Algeria, northern Mali and Mauritania, through which blow the dry near-surface northeasterly Harmattan winds, with a peak in dust emission around the low-lying Tidihelt region. North African orography is thought to contribute to the strength of the LLJ over the Bodele dust source in Chad, but its influence on erosivity over summertime source regions remains unquantified. In this paper, the contribution of central Saharan orography to the strength of Harmattan LLJs and associated dust emission frequency is tested. An idealized simulation with flattened Hoggar mountains is compared with a control using the Met Office Unified Model at 12 km horizontal resolution. In the absence of the Hoggar mountains, dust emission frequency estimated using an empirical relationship with surface wind speeds is found to decline across the entire northeasterly LLJ alley, including by 31% in the Tidihelt where composited jet surface winds drop from 9.0 to 7.3 m s(-1) under a more easterly regime. The mountains are linked to a low-level leeward geopotential height perturbation, with a northern limb reinforcing northeasterlies through the Tidihelt. Dome-shaped elevated heating situated over the Hoggar mountains explains the difference between the simulated wind fields in the two experiments. These findings suggest that central Saharan orography plays an important role in sustaining erosive dusty conditions during boreal summer.
英文关键词	mineral dust aerosols Sahara low-level jet orography emission mechanisms
类型	Article
语种	英语
开放获取类型	Green Accepted, hybrid
收录类别	SCI-E
WOS记录号	WOS:000730000500001
WOS关键词	DESERT DUST ; HEAT LOWS ; PART I ; CONVECTION ; SCHEME ; CYCLE ; PARAMETERIZATION ; CIRCULATION ; TRANSPORT ; DYNAMICS
WOS类目	Meteorology & Atmospheric Sciences
WOS研究方向	Meteorology & Atmospheric Sciences
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/374141
作者单位	[Harrison, Thomas Caton; Washington, Richard; Engelstaedter, Sebastian; Jones, Richard G.] Univ Oxford, Ctr Environm, Climate Res Lab, Oxford, England; [Harrison, Thomas Caton] British Antarctic Survey, Cambridge, England; [Jones, Richard G.; Savage, Nick H.] Met Off, Exeter, Devon, England
推荐引用方式 GB/T 7714	Harrison, Thomas Caton,Washington, Richard,Engelstaedter, Sebastian,et al. Influence of Orography Upon Summertime Low-Level Jet Dust Emission in the Central and Western Sahara[J],2021,126(23).
APA	Harrison, Thomas Caton,Washington, Richard,Engelstaedter, Sebastian,Jones, Richard G.,&Savage, Nick H..(2021).Influence of Orography Upon Summertime Low-Level Jet Dust Emission in the Central and Western Sahara.JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES,126(23).
MLA	Harrison, Thomas Caton,et al."Influence of Orography Upon Summertime Low-Level Jet Dust Emission in the Central and Western Sahara".JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 126.23(2021).