Dissimilarity between dust, heat, and momentum turbulent transports during aeolian soil erosion
RAJOT, J.-L
Laboratoire Interuniversitaire des Systèmes Atmosphériques [LISA (UMR_7583)]
Institut d'écologie et des sciences de l'environnement de Paris [iEES Paris]
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Laboratoire Interuniversitaire des Systèmes Atmosphériques [LISA (UMR_7583)]
Institut d'écologie et des sciences de l'environnement de Paris [iEES Paris]
RAJOT, J.-L
Laboratoire Interuniversitaire des Systèmes Atmosphériques [LISA (UMR_7583)]
Institut d'écologie et des sciences de l'environnement de Paris [iEES Paris]
Laboratoire Interuniversitaire des Systèmes Atmosphériques [LISA (UMR_7583)]
Institut d'écologie et des sciences de l'environnement de Paris [iEES Paris]
BOUET, C.
Institut d'écologie et des sciences de l'environnement de Paris [iEES Paris]
Laboratoire Interuniversitaire des Systèmes Atmosphériques [LISA (UMR_7583)]
< Réduire
Institut d'écologie et des sciences de l'environnement de Paris [iEES Paris]
Laboratoire Interuniversitaire des Systèmes Atmosphériques [LISA (UMR_7583)]
Langue
en
Article de revue
Ce document a été publié dans
Journal of Geophysical Research: Atmospheres. 2019-01-22, vol. 124, n° 2, p. 1064-1089
American Geophysical Union
Résumé en anglais
Measuring accurately size-resolved dust flux near the surface is crucial for better quantifying dust losses by semiarid soils. Dust fluxes have been usually estimated from the flux-gradient approach, assuming similarity ...Lire la suite >
Measuring accurately size-resolved dust flux near the surface is crucial for better quantifying dust losses by semiarid soils. Dust fluxes have been usually estimated from the flux-gradient approach, assuming similarity between dust and momentum turbulent transport. This similarity has, however, never been verified. Here we investigate the similarity between dust (0.3 to 6.0 m in diameter), momentum, and heat fluxes during aeolian erosion events. These three fluxes were measured by the Eddy Covariance technique during the WIND-O-V (WIND erOsion in presence of sparse Vegetation's) 2017 field experiment over an isolated erodible bare plot in South Tunisia. Our measurements confirm the prevalence of ejection and sweep motions in transporting dust as for heat and momentum. However, our measurements also reveal a different partition of the dust flux between ejection and sweep motions and between eddy time scales compared to that of momentum and heat fluxes. This dissimilarity results from the intermittency of the dust emission compared to the more continuous emission (absorption) of heat (momentum) at the surface. Unlike heat emission and momentum absorption, dust release is conditioned by the wind intensity to initiate sandblasting. Consequently, ejection motions do not carry dust as often as heat and low momentum from the surface. This dissimilarity diminishes with increasing wind intensity as saltation patterns, and thus dust emission through sandblasting, become spatially more frequent. Overall, these findings may have implications on the evaluation of dust flux from techniques based on similarity with momentum or heat turbulent transport.< Réduire
Mots clés en anglais
TUNISIA
SEMIARID AREA
Origine
Importé de halUnités de recherche