气候变化领域集成服务门户(CCPortal): Understanding the summertime diurnal cycle of precipitation over sub-Saharan West Africa: regions with daytime rainfall peaks in the absence of significant topographic features

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DOI	10.1007/s00382-018-4315-z
	Understanding the summertime diurnal cycle of precipitation over sub-Saharan West Africa: regions with daytime rainfall peaks in the absence of significant topographic features
	Vizy E.K.; Cook K.H.
发表日期	2019
ISSN	0930-7575
起始页码	2903
结束页码	2922
卷号	52 期号:2020-05-06
英文摘要	Convection-permitting regional model output is analyzed to better understand the diurnal cycle of rainfall during the height of the West African summer monsoon. This investigation focuses on two regions, the western Bodélé of Chad and eastern Burkina Faso, that have a propensity for daytime rainfall, but why this occurs does not conform to our conventional understanding of being directly associated with the presence of significant topographic feature(s). The August diurnal cycle of rainfall for the Bodélé is characterized by an afternoon peak, with mesoscale convective systems (MCSs) originating within 500 km accounting for 80% of the afternoon precipitation. These MCSs are associated with a deepening of the monsoon trough over the western Sahara related to northern storm track African easterly wave (AEW) disturbance activity, combined with anomalous ridging over eastern Chad associated with cold pool outflow from convection that originates over the Marra Mountains the previous afternoon. These circulation features enhance the moist low-level southwesterly flow and increase instability over the Bodélé. Over Burkina Faso rainfall has a primary afternoon peak, and a secondary morning peak. MCSs account for 95% of the total rainfall. Morning rainfall is primarily due to MCSs forming over the Damergou Gap of Niger, while the afternoon rainfall is associated with MCSs that originate over the Damergou Gap as well as locally. While both types of MCSs are associated with an approaching southern storm track AEW disturbance, it is differences in northern storm track activity that helps explain why some MCSs originate over the Damergou Gap. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	African easterly jet; African easterly wave disturbance; Cold pool outflow; Convection permitting modeling; Diurnal cycle of precipitation; Inter-tropical front; MCS genesis; Mesoscale convective system; Sahel; West Africa
语种	英语
scopus关键词	atmospheric convection; convective system; diurnal variation; easterly wave; jet stream; mesoscale meteorology; precipitation (climatology); rainfall; summer; topography; Sahel [Sub-Saharan Africa]; West Africa
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146475
作者单位	Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712, United States
推荐引用方式 GB/T 7714	Vizy E.K.,Cook K.H.. Understanding the summertime diurnal cycle of precipitation over sub-Saharan West Africa: regions with daytime rainfall peaks in the absence of significant topographic features[J],2019,52(2020-05-06).
APA	Vizy E.K.,&Cook K.H..(2019).Understanding the summertime diurnal cycle of precipitation over sub-Saharan West Africa: regions with daytime rainfall peaks in the absence of significant topographic features.Climate Dynamics,52(2020-05-06).
MLA	Vizy E.K.,et al."Understanding the summertime diurnal cycle of precipitation over sub-Saharan West Africa: regions with daytime rainfall peaks in the absence of significant topographic features".Climate Dynamics 52.2020-05-06(2019).