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| HAL : hal-00599914, version 1 |
| DOI : 10.1002/qj.844 |
| Fiche détaillée |  Récupérer au format |
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| Quarterly Quarterly Journal of the Royal Meteorological Society 137, 658 (2011) 1227-1240 |
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| Dust impact on the West African heat low in summertime |
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| Christophe Lavaysse 1Jean-Pierre Chaboureau 2 |
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| (2011) |
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| The impact of dust on a six-day pulsation of the West African heat low (WAHL) in summertime (14-20 July 2006) is investigated, with convective rainfall and dust bursts being observed over the Sahel at the beginning and end of the episode. Three Meso-NH simulations were designed which differed in their dust representation. All the simulations capture the variation in the WAHL intensity well, including the simulation without any dust effects. This shows the primary role of large-scale forcing on the WAHL pulsation. In spite of additional daytime heating and night-time cooling effects over the Sahara, the simulation with dust climatology resembles the simulation without any dust effects. In contrast, the simulation using a prognostic dust scheme enhances alternating northward advection of warm and dry air and southward advection of cold and wet air associated with the propagation of an African easterly wave, leading to a strengthening of the WAHL variabilities. This study highlights two effects of dust on the WAHL over the Sahara: a so-called direct effect associated with dust radiative heating, which increases the WAHL thickness, and a so-called indirect effect that intensifies both the African easterly jet and a related African easterly wave. |
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| 1 : | Department of Atmospheric and Oceanic Sciences, McGill University |
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McGill University |
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| 2 : | Laboratoire d'aérologie (LA) |
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CNRS : UMR5560 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III |
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| 3 : | Institut Pierre-Simon-Laplace (IPSL) |
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CNRS : FR636 – Institut de recherche pour le développement [IRD] – CEA – CNES – INSU – Université Pierre et Marie Curie [UPMC] - Paris VI – Université de Versailles Saint-Quentin-en-Yvelines – Ecole normale supérieure de Paris - ENS Paris |
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| 4 : | Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) |
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CNRS : UMR8190 – Université Pierre et Marie Curie [UPMC] - Paris VI – Université de Versailles Saint-Quentin-en-Yvelines – INSU |
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| Domaine | : | Planète et Univers/Sciences de la Terre/Climatologie Sciences de l'environnement/Milieux et Changements globaux Physique/Physique/Physique Atmosphérique et Océanique |
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| African easterly jet – African easterly wave – Monsoon flow |
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| hal-00599914, version 1 | |
| http://hal.archives-ouvertes.fr/hal-00599914 | |
| oai:hal.archives-ouvertes.fr:hal-00599914 | |
| Contributeur : Catherine Cardon | |
| Soumis le : Samedi 11 Juin 2011, 15:39:17 | |
| Dernière modification le : Lundi 25 Juillet 2011, 21:11:14 | |
