Understanding the variability of the rainfall dipole in West Africa using the EC-Earth last millennium simulation

Abstract There is a well-known mode of rainfall variability associating opposite hydrological conditions over the Sahel region and Gulf Guinea, forming dipole pattern. Previous meteorological observations show that pattern varies at interannual timescales. Using an EC-Earth climate model simulation for last millennium (850–1850 CE), we investigate in West Africa longer The 1000-year-long data this presents decadal to multidecadal centennial long-term trend. singular value decomposition (SVD) analysis, identified present first SVD with 60% explained variance associated variabilities tropical Atlantic sea surface temperature (SST). second shows monopole centred Sahel, extra-tropical SST variability. We conclude dipole-like natural originated from local ocean–atmosphere-land coupling basin. warm anomalies equatorial Ocean favour anomalous low pressure tropics. This weakens meridional gradient between Saharan Heat Low Atlantic. It leads northeasterly, reduces southwesterly moisture flux into confines Guinea's convergence. influence variability, such as oscillation, tends modify Guinea Sahara through influencing heat low. External forcing—such orbital forcing, solar radiation, volcanic land-use—can amplify/dampen thermal forcing atmosphere dynamical feedback.