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Monitoring hydrological variables from remote sensing and modelling in the Congo River basin
  • +12
  • Adrien Paris,
  • Stéphane Calmant,
  • Marielle Gosset,
  • Ayan Fleischmann,
  • Taina Conchy,
  • Jean-Pierre Bricquet,
  • Pierre-André Garambois,
  • Fabrice Papa,
  • Raphael Tshimanga,
  • Georges Gulemvuga Guzanga,
  • Vinicius Siqueira,
  • Blaise Tondo,
  • Rodrigo Cauduro Dias de Paiva,
  • Joecila Santos da Silva,
  • Alain Laraque
Adrien Paris
Ocean Next

Corresponding Author:adrien.paris@ocean-next.fr

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Stéphane Calmant
LEGOS-UMR5566 CNES/IRD/CNRS/UPS
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Marielle Gosset
GET-UMR5563 CNRS/IRD/UPS
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Ayan Fleischmann
UFRGS, Instituto de Pesquisas Hidraulicas
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Taina Conchy
Universidade do Estado do Amazonas, RHASA
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Jean-Pierre Bricquet
IRD, HydroSciences Montpellier
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Pierre-André Garambois
INRAE Centre d'Aix en Provence, UMR RECOVER
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Fabrice Papa
LEGOS-UMR5566 CNES/IRD/CNRS/UPS; Universidade de Brasilia
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Raphael Tshimanga
Université de Kinshasa, Congo Basin Water Resources Research Center
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Georges Gulemvuga Guzanga
CICOS, Building Kilou, 24 av. Wagenia
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Vinicius Siqueira
UFRGS, Instituto de Pesquisas Hidraulicas
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Blaise Tondo
CICOS, Building Kilou, 24 av. Wagenia
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Rodrigo Cauduro Dias de Paiva
UFRGS, Instituto de Pesquisas Hidraulicas
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Joecila Santos da Silva
Universidade do Estado do Amazonas, RHASA
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Alain Laraque
GET-UMR5563 CNRS/IRD/UPS
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Abstract

This study intends to integrate heterogeneous remote sensing observations and hydrological modelling into a simple framework to monitor hydrological variables in the poorly gauged Congo River basin (CRB). It focuses on the possibility to retrieve effective channel depths and discharges all over the basin in near real time (NRT). First, this paper discusses the complexity of calibrating and validating a hydrologic–hydrodynamic model (namely the MGB model) in the CRB. Next, it provides a twofold methodology for inferring discharge at newly monitored virtual stations (VSs, crossings of a satellite ground track with a water body). It makes use of remotely sensed datasets together with in-situ data to constrain, calibrate and validate the model, and also to build a dataset of stage/discharge rating curves (RCs) at 709 VSs distributed all over the basin. The model was well calibrated at the four gages with recent data (Nash-Sutcliffe Efficiency, NSE> 0.77). The satisfactory quality of RCs basin-wide (mean NSE between simulated discharge and rated discharge at VSs, NSEmean = 0.67) is an indicator of the overall consistency of discharge simulations even in ungauged upstream sub-basins. This RC dataset provides an unprecedented possibility of NRT monitoring of CRB hydrological state from the current operational satellite altimetry constellation. The discharges estimated at newly monitored locations proved to be consistent with observations. They can be used to increase the temporal sampling of water surface elevation (WSE) monitoring from space with no need for new model runs. The RC located under the fast sampling orbit of the SWOT satellite, to be flown in 2022, will be used to infer daily discharge in major contributors and in the Cuvette Centrale, as soon as data is released.
25 Feb 2022Published in Congo Basin Hydrology, Climate, and Biogeochemistry on pages 339-366. 10.1002/9781119657002.ch18