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Auteur Benjamin Sultan |
Documents disponibles écrits par cet auteur (2)
Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesOn the late northward propagation of the West African monsoon in summer 2006 in the region of Niger/Mali / Philippe Drobinski in Journal of geophysical research : Atmospheres, vol 114 n° D9 (2009)
Titre : On the late northward propagation of the West African monsoon in summer 2006 in the region of Niger/Mali Type de document : Article/Communication Auteurs : Philippe Drobinski, Auteur ; Sophie Bastin, Auteur ; Serge Janicot, Auteur ; Olivier Bock Année de publication : 2009 Projets : AMMA & AMMA-2 / Janicot, Serge Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] données GPS
[Termes IGN] données météorologiques
[Termes IGN] Mali
[Termes IGN] mousson
[Termes IGN] NigerRésumé : (auteur) This paper investigates the fine‐scale dynamical processes at the origin of the late northward migration of the monsoon flow in summer 2006 in the region of Niger and Mali (onset on 3 July 2006 compared to the climatological onset date, 24 June). Compared to a 28‐year climatology, 2006 NCEP‐2 reanalyses show evidence of an anomalous pattern during 10 days between 25 June and 3 July 2006, characterized by the African Easterly Jet (AEJ) blowing from the northeast along a narrow northeast/southwest band located over the Hoggar and Air mountains associated with an unusually strong northeasterly harmattan in the lee of the mountains. Using data collected during the African Monsoon Multidisciplinary Analysis (AMMA) experiment and mesoscale numerical simulations, this study shows evidence of interaction between the AEJ and the orography supported by the reduced gravity shallow water theory which explains the enhancement of the harmattan downstream of the Hoggar and Air mountains in summer 2006. The enhanced harmattan contributes to move southward the intertropical discontinuity (ITD) defined as the interface between the cool moist southwesterly monsoon flow and the warm dry harmattan. Finally, an interaction between the ITD and African Easterly waves contributes to propagate the ITD southward retreat about 1500 km to the west of the Hoggar and Air mountains. Numéro de notice : A2009-594 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2008JD011159 Date de publication en ligne : 13/05/2009 En ligne : https://doi.org/10.1029/2008JD011159 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96202
in Journal of geophysical research : Atmospheres > vol 114 n° D9 (2009)[article]
Titre : Multiscale analysis of precipitable water vapor over Africa from GPS data and ECMWF analyses Type de document : Article/Communication Auteurs : Olivier Bock Année de publication : 2007 Projets : 1-Pas de projet / Janicot, Serge Article en page(s) : 6 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique (géographie physique)
[Termes IGN] analyse multiéchelle
[Termes IGN] données GPS
[Termes IGN] données météorologiques
[Termes IGN] précipitation
[Termes IGN] vapeur d'eauRésumé : (auteur) This is the first climatological analysis of precipitable water vapor (PWV) from GPS data over Africa. The data reveal significant modulations and variability in PWV over a broad range of temporal scales. GPS PWV estimates are compared to ECMWF reanalysis ERA40. Both datasets show good agreement at the larger scales (seasonal cycle and inter‐annual variability), driven by large scale moisture transport. At intra‐seasonal (15–40 days) and synoptic (3–10 days) scales, strong PWV modulations are observed from GPS, consistently with ECMWF analysis. They are shown to be correlated with convection and the passage of equatorial waves and African Easterly waves. The high‐frequency GPS observations also reveal a significant diurnal cycle in PWV, which magnitude and spectral content depends strongly on geographic location and shows a seasonal modulation. The diurnal cycle of PWV is poorly represented in ERA40 reflecting weaknesses in the water cycle of global circulation models at this timescale. Numéro de notice : A2007-682 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2006GL028039 Date de publication en ligne : 09/05/2007 En ligne : https://doi.org/10.1029/2006GL028039 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95742
in Geophysical research letters > vol 34 n° 9 (16 May 2007) . - 6 p.[article]
