2.2. River discharge
The river discharge used in this study was obtained from the GRDC (Global Runoff Data Centre) archive (www.bafg.de/GRDC). The gauge station at the Congo Kinshasa station was used to study hydrological response of the Congo river to rainfall conditions. GRDC has several discontinuous and abandoned gauges distributed across the basin, however, the gauge at the Congo river in Kinshasa station has complete historical data (1903􀀀 2010) with no gaps. Because of its numerous discharges from tributaries that originates from Eastern Africa, this hydrological station is one of the most significant in the basin. Also, this gauge station showed considerable strong amplitude in monthly discharge and explained considerable multi-annual changes (more than 80% of variability) in the GRACE-hydrological signal of the Congo basin Ndehedehe et al. (2018). It is therefore logical to conclude that the discharge at Kinshasa station encapsulates most of the flows within the basin. Moreover, our analyses of observed relationship of discharge with rainfall were based on the common period for which both data are available.