Auteur : Alsdorf, D.

Co-Auteur : Beighley, E., Laraque, A., Lee, H., Tshimanga, R.M., O’Loughlin, F., Mahe, G., Dinga, B., Moukandi, G., Spencer, R.G.M Review : Reviews of Geophycs

Lien : https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016RG000517  

Abstract

We review the published results on the Congo Basin hydrology and summarize the historic andongoing research. Annual rainfall is ~1900 mm/yr along an east-west trend across the basin, decreasingnorthward and southward to ~1100 mm/yr. Historic studies using lysimeters, pans, and models suggest thatthe annual potential evapotranspiration varies little across the basin at 1100 to 1200 mm/yr. Over the pastcentury, river discharge data have been collected at hundreds of stream gauges with historic and recent dataat 96 locations now publicly available. Congo River discharge at Kinshasa-Brazzaville experienced an increaseof 21% during the 1960–1970 decade in comparison to most other decades. Satellite altimetry measurementsof high and low flows show that water levels in the “Cuvette Centrale” wetland are 0.5 m to 3.0 m higher inelevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about ameter and there does not appear to be many sizable channels across the “Cuvette”; thus, wetland flows arediffusive. Cuvette waters alone are estimated to emit about 0.5 Pg CH 4 and CO 2 equivalents/yr, an amountthat is significant compared to global carbon evasions. Using these results, we suggest seven hypotheses thatfocus on the source of the Cuvette waters and how these leave the wetland, on the river discharge generatedby historic rainfall, on the connection between climate change and the rainfall-runoff generated by themigrating “tropical rainbelt,” on deforestation and hydroelectric power generation, and on the amount ofcarbon emitted from Congo waters.