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Communication Dans Un Congrès Année : 2018

Wind erosion and dust emission in the Sahel: a regional modelling approach to evaluate the impact of climate and land-use

Abdourhamane Touré
  • Fonction : Auteur
A. Abdourhamanetouré
  • Fonction : Auteur
F. Couvreux
  • Fonction : Auteur
  • PersonId : 955674
Manuela Grippa
  • Fonction : Auteur
  • PersonId : 861032
Pierre Hiernaux
  • Fonction : Auteur
  • PersonId : 862126
Yann Largeron
  • Fonction : Auteur
Éric Mougin
  • Fonction : Auteur
  • PersonId : 867982
Amadou Didier Tidjani
  • Fonction : Auteur
T. Vischel
  • Fonction : Auteur
  • PersonId : 851527

Résumé

The semi-arid Sahelian region is particularly prone to wind erosion due to low and variable annual precipitation producing low vegetation cover with a high interannual variability. Surfaces traditionally devoted to livestock grazing are used as croplands, increasing the proportion of bare surface unprotected from wind erosion. Wind erosion could significantly evolve in the future with climate change and the changes in land use and agropastoral management practices expected from the persistent demographic growth. To estimate the wind erosion and dust emission in the Sahel, we have developed a regional modelling approach in the framework of the CAVIARS ANR project (Climate, Agriculture and Vegetation: Impacts on Aeolian eRosion in the Sahel). The approach is based on existing models that were adapted and coupled to represent the main processes involved in the wind erosion and their dependence to climate parameters and agropastoral practices. Natural vegetation (herbaceous) and cropped vegetation (millet) are respectively modelled with the STEP vegetation model and the SARRA-H agronomic model,both models improved to reproduce the dynamics of dry vegetation. The wind erosion model has been tested and adapted to represent the erosion fluxes over typical Sahelian vegetated surfaces. A specific parameterization have been developed to represent the very strong surface winds associated to the convective activity. Grazing pressure maps were established based on national data and/or agro-pastoral census. The spatial and temporal distribution of the simulated dust emissions computed for the period 2000-2014 will be presented. The parameterization of the wind speed distribution associated with the convective activity allows to better capture the seasonal pattern of local wind erosion. The relative weight of climatic parameters and agropastoral management will be estimated by reference to a simulation with no vegetation and no land use.
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Dates et versions

hal-02333362 , version 1 (25-10-2019)

Identifiants

  • HAL Id : hal-02333362 , version 1

Citer

Abdourhamane Touré, Beatrice Marticorena, G. Siour, Caroline Pierre, Christel Bouet, et al.. Wind erosion and dust emission in the Sahel: a regional modelling approach to evaluate the impact of climate and land-use. les 30 ans d'Amma-Catch, Dec 2018, Niamey, Niger. ⟨hal-02333362⟩
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