Mineral dust over west and central Sahel: Seasonal patterns of dry and wet deposition fluxes from a pluriannual sampling (2006-2012) - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research: Atmospheres Année : 2017

Mineral dust over west and central Sahel: Seasonal patterns of dry and wet deposition fluxes from a pluriannual sampling (2006-2012)

M. Coulibaly
  • Fonction : Auteur
I. Kone
  • Fonction : Auteur

Résumé

Total and wetmineral dust deposition has beenmonitored since 2006 at three Sahelian stations in Senegal, Mali, and Niger, respectively at the weekly and the event time scale. Average annual deposited mass fluxes range from 75 to 183 gm(-2) yr(-1), from west to east. Deposition fluxes exhibit a clear seasonal cycle in Mali and Niger. High wet deposition fluxes result from an optimum phasing between dust concentration and precipitation: the maximum occurring at the beginning of the wet season, after the maximum of dust concentration and before the precipitation maximum. The contribution of wet to total deposition varies from 67% in Mali to 8% in Senegal. It is the main factor of variability of the deposition fluxes from year to year and at the seasonal scale in Niger and Mali. Wet deposition fluxes in Mali and Niger are mainly due to the wash out of dust emitted by convective systems. In Senegal, the deposition fluxes are lower and dominated by dry deposition (92% of the annual deposition flux). This is due to the low occurrence of convective systems producing local dust emissions and intense wet deposition. The dry deposition fluxes are primarily driven by the variability of the dust concentration. The dry deposition velocities derived from our measurements are consistent with those estimated by theoretical models. Scavenging ratios computed from the measured wet deposition fluxes, dust concentrations, and precipitation are anticorrelated with precipitation amounts. This suggests that most of the atmospheric dust is scavenged at the very beginning of the precipitation events.
Fichier principal
Vignette du fichier
2017_Marticorena_Journal of Geophysical Research - Atmospheres_1.pdf (3.27 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-01600639 , version 1 (26-05-2020)

Licence

Paternité - Partage selon les Conditions Initiales

Identifiants

Citer

B. Marticorena, B. Chatenet, Jean-Louis Rajot, G. Bergametti, A. Deroubaix, et al.. Mineral dust over west and central Sahel: Seasonal patterns of dry and wet deposition fluxes from a pluriannual sampling (2006-2012). Journal of Geophysical Research: Atmospheres, 2017, 122 (2), pp.1338-1364. ⟨10.1002/2016JD025995⟩. ⟨hal-01600639⟩
129 Consultations
89 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More