[Figure 11]
The inter-annual variations and cumulative departures of rainfall and discharge were also explored to understand their interactions in the Congo basin (Fig. 9). The inter-annual variations during the 1901- 2010 period was consistent and captures the wettest period (1960- 1970) in the basin (Fig. 9a). Their cumulative departures are somewhat similar but show an apparent inconsistent trend during the 1930-1950 and post 1999- 2010 periods (Figs. 9b-c). Generally, there seems to be a change in the hydrological regimes of the Congo river, (especially after 1994) owing to the rather pervasive influence of extreme droughts. This again could be the aftermath of extreme droughts, which fluctuated between 50% (i.e., affected areas) in the early years of the century and 40% during the 1994-2014 period (Ndehedehe et al., 2019). This change is reflected in the observed temporal relationship between maximum rainfall and discharge (Figs. 10a-d). For example, the rainfall-discharge relationship was stronger in 1961-1990 (r = 0. 77) and 1991-2010 (r = 0. 69) compared with other climatological periods when correlations were weak (Figs. 10c and d). Moreover, the temporal series associated with the ICA-localised spatial rainfall patterns over the Congo basin are correlated with discharge (Fig. 11). As shown in the leading independent modes (Fig. 11), the discharge-rainfall relationship is strongest at the extreme south (r = 0. 65) and north (r = 0. 64) of the basin. These sections of the basin are characterised by considerable amplitudes in annual and seasonal rainfall (EOF-1, Figs. 5a-b, 6a-b and cf. 3). The relationship (rainfall and discharge) is also significant in other catchments where correlations of 0.56, 0.59 and 0.51 have been observed although temporal relationships of localised rainfall at the equator with discharge are poor and insignificant (α = 0. 05). Given the trajectory of water inflow in the Congo basin, the considerable association of rainfall with discharge implies that the wetland hydrology of the Cuvette central is nourished mostly by rainfall, in addition to exchanges of fluxes in the floodplain wetlands.