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DOI	10.1175/MWR-D-19-0342.1
	Potential Vorticity Generation by West African Squall Lines
	Johnson, Richard H.; Ciesielski, Paul E.
通讯作者	Johnson, RH
来源期刊	MONTHLY WEATHER REVIEW
ISSN	0027-0644
EISSN	1520-0493
出版年	2020
卷号	148 期号:4 页码:1691-1715
英文摘要	The West African summer monsoon features multiple, complex interactions between African easterly waves (AEWs), moist convection, variable land surface properties, dust aerosols, and the diurnal cycle. One aspect of these interactions, the coupling between convection and AEWs, is explored using observations obtained during the 2006 African Monsoon Multidisciplinary Analyses (AMMA) field campaign. During AMMA, a research weather radar operated at Niamey, Niger, where it surveilled 28 squall-line systems characterized by leading convective lines and trailing stratiform regions. Nieto Ferreira et al. found that the squall lines were linked with the passage of AEWs and classified them into two tracks, northerly and southerly, based on the position of the African easterly jet (AEJ). Using AMMA sounding data, we create a composite of northerly squall lines that tracked on the cyclonic shear side of the AEJ. Latent heating within the trailing stratiform regions produced a midtropospheric positive potential vorticity (PV) anomaly centered at the melting level, as commonly observed in such systems. However, a unique aspect of these PV anomalies is that they combined with a 400-500-hPa positive PV anomaly extending southward from the Sahara. The latter feature is a consequence of the deep convective boundary layer over the hot Saharan Desert. Results provide evidence of a coupling and merging of two PV sources-one associated with the Saharan heat low and another with latent heating-that ends up creating a prominent midtropospheric positive PV maximum to the rear of West African squall lines.
类型	Article
语种	英语
开放获取类型	Bronze
收录类别	SCI-E
WOS记录号	WOS:000591341900013
WOS关键词	ATMOSPHERIC BOUNDARY-LAYER ; TROPICAL CLOUD CLUSTERS ; SAHARAN AIR LAYER ; 23 JUNE 1981 ; EASTERLY WAVES ; THERMODYNAMIC STRUCTURE ; WEATHER SYSTEMS ; BUDGET ANALYSES ; SUMMER MONSOON ; DIURNAL CYCLE
WOS类目	Meteorology & Atmospheric Sciences
WOS研究方向	Meteorology & Atmospheric Sciences
来源机构	Colorado State University
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/327585
作者单位	[Johnson, Richard H.; Ciesielski, Paul E.] Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA
推荐引用方式 GB/T 7714	Johnson, Richard H.,Ciesielski, Paul E.. Potential Vorticity Generation by West African Squall Lines[J]. Colorado State University,2020,148(4):1691-1715.
APA	Johnson, Richard H.,&Ciesielski, Paul E..(2020).Potential Vorticity Generation by West African Squall Lines.MONTHLY WEATHER REVIEW,148(4),1691-1715.
MLA	Johnson, Richard H.,et al."Potential Vorticity Generation by West African Squall Lines".MONTHLY WEATHER REVIEW 148.4(2020):1691-1715.