气候变化领域集成服务门户(CCPortal): Influence of Walker circulations on East African rainfall

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DOI	10.1007/s00382-020-05579-7
	Influence of Walker circulations on East African rainfall
	Zhao S.; Cook K.H.
发表日期	2021
ISSN	0930-7575
卷号	56 期号:2021-07-08
英文摘要	Walker circulations near East Africa are identified and their influence on the interannual variability of East African rainfall is explored in multiple reanalyses and observational precipitation datasets. The robustness of methodology for identifying 2-dimensional overturning circulations in a three-dimensional flow is investigated. Three Walker circulations with potential relevance to East African rainfall are identified, namely, the East African, the Congo Basin, and the Indian Ocean Walker circulations. Consistent anti-correlations across the reanalyses exist for the upward and downward branches of the Indian Ocean Walker Circulation during September–March, with strongest connections during October–December; they do not emerge for the other two Walker circulations. Less (more) precipitation occurs over East Africa in the short-rains season when the Indian Ocean Walker Circulation is anomalously strong (weak). These rainfall variations are associated with anomalous mid-level moisture divergence that primarily results from variations in wind divergence rather than atmospheric moisture. The anomalous horizontal advection of moist static energy can be important in modulating convection, but this argument is not conclusive considering the unclosed budget and the variations within the composites. The associations above do not indicate causality. Caution is advisable when using the concept of Walker circulations because a two-dimensional stream function can over-simplify the complexity of the three-dimensional circulation. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
英文关键词	Congo basin Walker circulation; East Africa; East African precipitation; East African short rains; Indian Ocean Walker circulation; Walker circulation
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/183338
作者单位	Department of Geological Sciences, University of Texas at Austin, Austin, TX, United States
推荐引用方式 GB/T 7714	Zhao S.,Cook K.H.. Influence of Walker circulations on East African rainfall[J],2021,56(2021-07-08).
APA	Zhao S.,&Cook K.H..(2021).Influence of Walker circulations on East African rainfall.Climate Dynamics,56(2021-07-08).
MLA	Zhao S.,et al."Influence of Walker circulations on East African rainfall".Climate Dynamics 56.2021-07-08(2021).