Abstract
Original language | English |
---|---|
Pages (from-to) | 139-155 |
Number of pages | 7 |
Journal | Theoretical and Applied Climatology |
Volume | 121 |
Issue number | 1 |
Early online date | 23 Jul 2014 |
DOIs | |
Publication status | Published - Jul 2015 |
Fingerprint
Keywords
- Sahel rainfall
- Atlantic sea surface temperature
Cite this
Low-frequency variability and zonal contrast in Sahel rainfall and Atlantic sea surface temperature teleconnections during the last century. / Dieppois, Bastien; Durand, Alain; Fournier, Matthieu; Diedhiou, Arona; Fontaine, Bernard; Massei, Nicolas; Nouaceur, Zeinnedine; Sebag, David .
In: Theoretical and Applied Climatology, Vol. 121, No. 1, 07.2015, p. 139-155.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Low-frequency variability and zonal contrast in Sahel rainfall and Atlantic sea surface temperature teleconnections during the last century
AU - Dieppois, Bastien
AU - Durand, Alain
AU - Fournier, Matthieu
AU - Diedhiou, Arona
AU - Fontaine, Bernard
AU - Massei, Nicolas
AU - Nouaceur, Zeinnedine
AU - Sebag, David
PY - 2015/7
Y1 - 2015/7
N2 - 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).
AB - 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).
KW - Sahel rainfall
KW - Atlantic sea surface temperature
U2 - 10.1007/s00704-014-1229-5
DO - 10.1007/s00704-014-1229-5
M3 - Article
VL - 121
SP - 139
EP - 155
JO - Theorectical and Applied Climatology
JF - Theorectical and Applied Climatology
SN - 0177-798X
IS - 1
ER -