DOI: 10.1007/s00382-013-1673-4
Scopus记录号: 2-s2.0-84891630115
论文题名: Oceanic influence on the sub-seasonal to interannual timing and frequency of extreme dry spells over the West African Sahel
作者: Salack S. ; Giannini A. ; Diakhaté M. ; Gaye A.T. ; Muller B.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2014
卷: 42, 期: 2017-01-02 起始页码: 189
结束页码: 201
语种: 英语
英文关键词: Extreme dry spells
; Niger and Senegal
; Regional Occurrence Index
; Seasonality
; Spatial coherence
; SST anomaly
; West African Sahel
英文摘要: Intra-seasonal drought episodes (extreme dry spells) are strongly linked to crop yield loss in the West African Sahel, especially when they occur at crop critical stages such as juvenile or flowering stage. This paper seeks to expose potentially predictable features in the sub-seasonal to inter-annual occurrence of "extreme dry spells" (extDS) through their links to sea surface temperature anomalies (SSTAs). We consider two kinds of extreme dry spells: more than 2 weeks of consecutive dry days following a rain event (often found at the beginning of the rainy season, after the first rain events) and more than a week (observed towards the end of the rainy season, before the last rain events). We extract dry spells from daily rainfall data at 43 stations (31 stations in Senegal over 1950-2010 and 12 stations in Niger over 1960-2000) to identify the intra-seasonal distribution of extDS and their significant correlation with local rainfall deficits. Seasonality of distribution and high spatial coherence are found in the timing and the frequency of occurrence of extDS in different rainfall regions over Niger and Senegal. The correlation between the regional occurrence index (ROI), necessary to capture the spatial extent of extDS, and observed global sea surface temperature anomalies (SSTAs) sheds light on the influence of the external factors on the decadal, interannual and sub-seasonal variability of extDS over the West African Sahel. When the global tropics and the Atlantic are warmer than normal, more coherent and delayed June-July extDS are observed after onset of rainy season, as well as early cessation type in August-September. When the Indo-Pacific is cooler and the equatorial south Atlantic is warmer than normal little to no extDS are found in the onset sub-period of the monsoon season. Mostly late types of extDS occur in October as a result of late cessation. These results show potential predictability of extreme dry spells after onset and before cessation of monsoonal rain based on global patterns of sea surface temperature anomalies. © 2013 Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54671
Appears in Collections: 过去全球变化的重建
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作者单位: Laboratoire de Physique de l'Atmosphère et de l'Océan-Siméon Fongang, Ecole Supérieure Polytechnique, Université Cheikh Anta Diop, BP 5085 Dakar-Fann, Dakar, Senegal; Centre d'Etude Régional pour l'Amélioration de l'Adaptation a la Secheresse (CERAAS), BP 3320 Thiès Escale, Thiès, Senegal; International Research Institute for Climate and Society, The Earth Institute, Columbia University, NY, NY, United States; Centre International de Recherche Agronomique pour le Développement (CIRAD), UMR, AGAP, 34398 Montpellier, France; Africa Rice Center, AfricaRice, Sahel Regional Station, BP 96, Saint-Louis, Senegal
Recommended Citation:
Salack S.,Giannini A.,Diakhaté M.,et al. Oceanic influence on the sub-seasonal to interannual timing and frequency of extreme dry spells over the West African Sahel[J]. Climate Dynamics,2014-01-01,42(2017-01-02)