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.