Publications des scientifiques de l'IRD

Dieppois B., Durand A., Fournier M., Diedhiou Arona, Fontaine B., Massei N., Nouaceur Z., Sebag David. (2015). Low-frequency variability and zonal contrast in Sahel rainfall and Atlantic sea surface temperature teleconnections during the last century. Theoretical and Applied Climatology, 121 (1-2), p. 139-155. ISSN 0177-798X.

Titre du document
Low-frequency variability and zonal contrast in Sahel rainfall and Atlantic sea surface temperature teleconnections during the last century
Année de publication
2015
Type de document
Article référencé dans le Web of Science WOS:000356539300013
Auteurs
Dieppois B., Durand A., Fournier M., Diedhiou Arona, Fontaine B., Massei N., Nouaceur Z., Sebag David
Source
Theoretical and Applied Climatology, 2015, 121 (1-2), p. 139-155 ISSN 0177-798X
This study systematically examines teleconnections between Atlantic sea surface temperature (SST) and the west-east distribution of Sahel rainfall throughout the twentieth century, taking nonstationarity into account. Sahel rainfall variability of six selected rain gauges displays three dominant time scales: multi-decadal (> 20 years), quasi-decadal (8-18 years) and interannual (2-8 years). Regarding their patterns of low-frequency scales, three coherent Sahelian subregions can be identified: the Atlantic Coast (Dakar), western-central Sahel (Nioro and Mopti) and eastern Sahel (Niamey, Maradi, Maine-Soroa). Cross-analyses combining spectral and multivariate analyses of 20 station-based data and West-African gridded rainfall data statistically confirm dissimilarities between the western and eastern Sahel. Western and eastern Sahel rainfall data are correlated with SSTs from different regions of the Atlantic Ocean, especially in the North and tropical South Atlantic. As determined by wavelet coherence and phase, in-phase relationship with North Atlantic SSTs only occurs in wet periods and at the multi- and quasi-decadal scales. This teleconnection depends on the time period and the time scale, displaying a NW-SE pattern, which suggests nonuniform modulations of meridional displacements of the Intertropical Convergence Zone (ITCZ). Tropical South Atlantic SST variability is often related to opposite patterns between the Gulf of Guinean Coast (in phase) and Sahel region (out of phase).
Plan de classement
Sciences du milieu [021] ; Limnologie physique / Océanographie physique [032] ; Hydrologie [062]
Description Géographique
SENEGAL ; MALI ; NIGER ; SAHEL ; ATLANTIQUE
Localisation
Fonds IRD [F B010064761]
Identifiant IRD
fdi:010064761
Contact