Hydrological Reanalysis for the Congo River Basin (1983-2022) unchanged by synoptic observations

The Congo River basin (CRB), the world's second-largest river system, is subject to extreme hydrological events that strongly impact its ecosystems and population. Here we present an unprecedented 40-year (1983-2022) hydrological reanalysis of CRB daily discharge. To develp this dataset, we employ a large-scale hydrologic-hydrodynamic model (MGB) with lake storage dynamics representation and a data assimilation (DA) technique using in-situ discharge and water level observations. This is a variant of Wongchuig et al. (2023), which assimilates only the stations with the most complete data over the period 1981-2022, meaning that it is independent of synoptic observations occurring in certain periods such as radar altimetry since 2002 or in-situ observations of incomplete stations. This results in a more homogeneous performance over the time coverage for a proper trend analysis. The original simulation period was from 1981 but the first two years were removed to avoid inconsistencies due to model initial conditions.