Articles | Volume 8, issue 3
Earth Syst. Dynam., 8, 653–675, 2017
https://doi.org/10.5194/esd-8-653-2017

Special issue: The 8th EGU Leonardo Conference: From evaporation to precipitation:...

Earth Syst. Dynam., 8, 653–675, 2017
https://doi.org/10.5194/esd-8-653-2017

Research article 04 Aug 2017

Research article | 04 Aug 2017

A Lagrangian perspective of the hydrological cycle in the Congo River basin

Rogert Sorí1, Raquel Nieto1,2, Sergio M. Vicente-Serrano3, Anita Drumond1, and Luis Gimeno1 Rogert Sorí et al.
  • 1Environmental Physics Laboratory (EphysLab), Universidade de Vigo, Ourense, 32004, Spain
  • 2Department of Atmospheric Sciences, Institute of Astronomy, Geophysics and Atmospheric Sciences, University of São Paulo, São Paulo, 05508-090, Brazil
  • 3Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas (IPE-CSIC), Zaragoza, 50059, Spain

Abstract. The Lagrangian model FLEXPART is used to identify the moisture sources of the Congo River basin (CRB) and investigate their role in the hydrological cycle. This model allows us to track atmospheric parcels while calculating changes in the specific humidity through the budget of evaporation minus precipitation. This method permits the annual-scale identification of five continental and four oceanic principal regions that provide moisture to the CRB from both hemispheres over the course of the year. The most important is the CRB, which provides more than 50 % of the total atmospheric moisture contribution to precipitation over itself. Additionally, both the land that extends to the east of the CRB and the eastern equatorial South Atlantic Ocean are very important sources, while the Red Sea source is merely important in the (E − P) budget over the CRB despite its high evaporation rate. The moisture-sink patterns over the CRB in air masses that were tracked forward in time from all the sources follow the latitudinal rainfall migration and are mostly highly correlated with the pattern of the precipitation rate, ensuring a link between them. In wet (dry) years, the contribution of moisture to precipitation from the CRB over itself increases (decreases). Despite the enhanced evaporative conditions over the basin during dry years, the vertically integrated moisture flux (VIMF) divergence inhibits precipitation and suggests the transport of moisture from the CRB to remote regions.

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