3.1.1. GPCC vs CRU based precipitation estimates
The Congo basin precipitation estimates and its uncertainties are important issues that sometimes results in polarized debates and divergent opinions amongst climate researchers who have worked in the region (Ndehedehe et al., 2019). The challenging terrain, environmental conditions, and limited gauge observations in the Congo basin are some reasons for the poor understanding of precipitation estimates. Although time constraints (i.e., availability of historical observations) was a deciding factor in our choice of precipitation, as earlier mentioned (Section 2.1), the error variance in GPCC and CRU is significantly less compared to satellite products. Apart from disturbance of ecological assets and alteration to the Congo forest through prolonged drought and deforestation, the influence of topography on the Central African hydrology and its neighbouring East African countries cannot be overlooked. As with the influence of topographical variability and gauge density on precipitation products in the surrounding East African countries (Agutu et al., 2020), the Rift valley highlands in East Africa was earlier identified as an important driver of considerable anomaly in precipitation over the Congo basin (Bell et al., 2015). But the availability of in situ data to improve process-based knowledge on these drivers and monitor these conditions, including land surface conditions, local water recycling activity and contributions from oceanic hot spots is an issue for the Congo basin. It is true that a history of hydrological measurement exists in the Congo basin (Alsdorf et al., 2016).