Transport of dust particles from the Bodélé region to the monsoon layer - AMMA case study of the 9-14 June 2006 periodReport as inadecuate




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1 CNRM-GAME - Groupe d-étude de l-atmosphère météorologique 2 LaMP - Laboratoire de météorologie physique 3 Équipe Troposphère CNRM-GAME - Groupe d-étude de l-atmosphère météorologique, LACy - Laboratoire de l-Atmosphère et des Cyclones 4 SEE - School of Earth and Environment Leeds 5 SPACE - LATMOS LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales 6 O-FSI - Organization of Frontier Science and Innovation Kanazawa 7 LISA - Laboratoire inter-universitaire des systèmes atmosphèriques

Abstract : Aerosol properties were measured during an airborne campaign experiment that took place in June 2006 in West Africa within the framework of the African Monsoon Multidisciplinary Analyses AMMA. The goal of the present study was to determine the process that facilitates the sedimentation of dust particles from the Saharan Air Layer SAL to the boundary layer. A significant change in the dust particle concentration measured along the meridian between Niamey Niger and Cotonou Benin was found in the boundary layer ~700 m, where the dust particle concentration increased in a zone where local emission is not possible. Moreover, the boundary layer top observed with the dropsondes launched with the F-F20 shows a strong relationship with the surface cover anomalies, with higher Boundary Layer BL tops over the warmer surfaces, such as croplands, as opposed to adjacent forest. A mesoscale atmospheric model with a new on-line dust parameterization, resulting from the Alfaro and Gomes 2001 parametrisation and AMMA observations, was used to interpret the impact of vegetation anomalies on dust particle sedimentation. The results of the simulation are consistent with the observations, with higher dust over the warm surface cover anomalies.





Author: S. Crumeyrolle - Pierre Tulet - L. Gomes - L. Garcia-Carreras - Cyrille Flamant - D. J. Parker - A. Matsuki - P. Formenti - A. Sc

Source: https://hal.archives-ouvertes.fr/



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