DOI: 10.1007/s00382-013-1953-z
Scopus记录号: 2-s2.0-84905009985
论文题名: Impact of cold air surges on rainfall variability in the Sahel and wet African tropics: A multi-scale analysis
作者: Vizy E.K. ; Cook K.H.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2014
卷: 43, 期: 2017-03-04 起始页码: 1057
结束页码: 1081
语种: 英语
英文关键词: African rainfall
; Cold air surge
; Sahara
; Sahel
; Seasonal rainfall variability
; Synoptic rainfall variability
; Tropical Africa
英文摘要: Satellite-derived rainfall estimates and the ERA-Interim reanalysis are used to better understand cold air surge/precipitation interactions and to identify the implications for rainfall variability in the Sahel and tropical Africa on synoptic to seasonal timescales. At the synoptic timescale, cold air surges are associated with cold conditions over the eastern Sahara throughout the year due to the eastward passage of surface low pressure systems over the Mediterranean and the subsequent ridging over northern Africa. Rainfall decreases over central and eastern Africa approximately 4-5 days after the cold air first arrives in northeastern Africa. These precipitation anomalies persist for 4 or more days. At the seasonal timescale, a significant relationship between eastern Saharan low-level temperatures and rainfall in the Sahel and tropical Africa is identified, with colder conditions associated with reduced convection on the northern flank of the primary convergence zone, and vice versa. During boreal winter, the anomalous rainfall occurs over tropical Africa (0°N-8°N). During the summer, rainfall anomalies associated with cold air surges occur over the Sahel (10°N-16°N). These relationships are mediated by anomalous anticyclonic flow over northwestern Africa and western Europe. The analysis shows that cold air surges are significantly associated with summertime cooling over the Sahara, but less so during the winter. © 2013 Springer-Verlag Berlin Heidelberg. 资助项目: NSF, National Science Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54571
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, Austin, TX, 78712, United States
Recommended Citation:
Vizy E.K.,Cook K.H.. Impact of cold air surges on rainfall variability in the Sahel and wet African tropics: A multi-scale analysis[J]. Climate Dynamics,2014-01-01,43(2017-03-04)