DOI: 10.1007/s00382-014-2120-x
Scopus记录号: 2-s2.0-84896416574
论文题名: The relationship between African easterly waves and daily rainfall over West Africa: observations and regional climate simulations
作者: Crétat J. ; Vizy E.K. ; Cook K.H.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2014
卷: 44, 期: 2017-01-02 起始页码: 385
结束页码: 404
语种: 英语
英文关键词: African easterly waves
; Daily intense/extreme rainfall events
; Regional climate model
; Sahel
; West Africa
英文摘要: The relationship between summer African easterly waves (AEWs) and daily rainfall is assessed in West Africa for 1998–2008 using various reanalyses, satellite-derived rainfall products, and a regional climate model (RCM) run at 90- and 30-km resolutions. 3–5 and 6–9 day AEWs are extracted by filtering daily 700 hPa meridional wind time series at 1°W and 11.5°N, and 1°W and 17.5°N, respectively. Both observed and simulated rainfall anomalies are of larger magnitude over West Africa during 3–5-d than 6–9-d AEWs. The RCM simulates larger rainfall rates in phase with the 3–5-d wave trough instead of ahead, unlike the observations, and overestimates the intensity and spatial coverage of rainfall associated with 6–9-d AEWs. The observed and simulated co-variability between 3–5-d (6–9-d) AEW activity and daily rainfall is strong (weak) and mostly located south (north) of 15°N. However, the RCM overestimates the spatial coverage of the AEW–rainfall relationship in the longitudinal (latitudinal) direction in the case of 3–5-d (6–9-d) AEWs. Observed and simulated daily intense rainfall events, extracted using a percentile threshold approach, are mostly located south of 15°N during summer. The observed relationship between their frequency of occurrence and active 3–5-d AEWs is maximal west of 8°E, while extends up to southern Chad in both RCM simulations. Their magnitude is also largely overestimated by the RCM, indicating an exaggerated coupling between the wave activity and the convection. Finally, observed and simulated 3–5-d AEWs establish the most favorable synoptic conditions for the development of intense rainfall events over West Africa. © 2014, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54364
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, United States
Recommended Citation:
Crétat J.,Vizy E.K.,Cook K.H.. The relationship between African easterly waves and daily rainfall over West Africa: observations and regional climate simulations[J]. Climate Dynamics,2014-01-01,44(2017-01-02)