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Auteur Pascal Roucou |
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Affiner la recherche Interroger des sources externesThe large‐scale water cycle of the West African monsoon / Olivier Bock in Atmospheric Science Letters, vol 12 n° 1 (January - March 2011)
Titre : The large‐scale water cycle of the West African monsoon Type de document : Article/Communication Auteurs : Olivier Bock Année de publication : 2011 Projets : AMMA & AMMA-2 / Janicot, Serge Article en page(s) : pp 51 - 57 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] bilan hydrique
[Termes IGN] coordonnées GPS
[Termes IGN] données météorologiques
[Termes IGN] modèle météorologique
[Termes IGN] mousson
[Termes IGN] vapeur d'eau
[Termes IGN] variation saisonnièreRésumé : (Auteur) The vertically integrated water budget of West Africa is investigated with a hybrid dataset based on observational and modelling products elaborated by the African Monsoon Multidisciplinary Analyses (AMMA) and with several numerical weather prediction (NWP) products including the European Centre for Medium‐Range Weather Forecasts (ECMWF) AMMA reanalysis. Seasonal and intraseasonal variations are quantified over the period 2002–2007. Links between the budget terms are analyzed regionally, from the Guinean coast to the Sahel zone. Water budgets from the NWP systems are intercompared and evaluated against the hybrid dataset. Large deficiencies are evidenced in all the NWP products. Hypotheses are proposed about their origins and several improvements are foreseen. Copyright © 2010 Royal Meteorological Society. Numéro de notice : A2011-593 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/asl.288 Date de publication en ligne : 16/08/2010 En ligne : https://doi.org/10.1002/asl.288 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91516
in Atmospheric Science Letters > vol 12 n° 1 (January - March 2011) . - pp 51 - 57[article]
Titre : West African Monsoon water cycle: 1. A hybrid water budget data set Type de document : Article/Communication Auteurs : Rémi Meynadier, Auteur ; Olivier Bock Année de publication : 2010 Article en page(s) : 21 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] bilan hydrique
[Termes IGN] coordonnées GPS
[Termes IGN] données météorologiques
[Termes IGN] évapotranspiration
[Termes IGN] mousson
[Termes IGN] précipitation
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] variation saisonnièreRésumé : (auteur) This study investigates the West African Monsoon water cycle with the help of a new hybrid water budget data set developed within the framework of the African Monsoon Multidisciplinary Analyses. Surface water and energy fluxes are estimated from an ensemble of land surface model simulations forced with elaborate precipitation and radiation products derived from satellite observations, while precipitable water tendencies are estimated from numerical weather prediction analyses. Vertically integrated atmospheric moisture flux convergence is estimated as a residual. This approach provides an advanced, comprehensive atmospheric water budget, including evapotranspiration, rainfall, and atmospheric moisture flux convergence, together with other surface fluxes such as runoff and net radiation. The annual mean and the seasonal cycle of the atmospheric water budget are presented and the couplings between budget terms are discussed for three climatologically distinct latitudinal bands between 6°N and 20°N. West Africa is shown to be alternatively a net source and sink region of atmospheric moisture, depending on the season (a source during the dry season and a sink during the wet season). Several limiting and controlling factors of the regional water cycle are highlighted, suggesting strong sensitivity to atmospheric dynamics and surface radiation. Some insight is also given into the underlying smaller‐scale processes. The relationship between evapotranspiration and precipitation is shown to be very different between the Sahel and the regions more to the south and partly controlled by net surface radiation. Strong correlations are found between precipitation and moisture flux convergence over the whole region from daily to interannual time scales. Causality is also established between monthly mean anomalies. Hence, precipitation anomalies are preceded by moisture flux convergence anomalies and followed by moisture flux divergence and evapotranspiration anomalies. The results are discussed in comparison to other studies. Numéro de notice : A2010-653 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2010JD013917 Date de publication en ligne : 01/10/2010 En ligne : https://doi.org/10.1029/2010JD013917 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91724
in Journal of geophysical research : Atmospheres > vol 115 n° D19 (2010) . - 21 p.[article]Documents numériques
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West African Monsoon water cycle 1 - pdf éditeurAdobe Acrobat PDF
Titre : Assessment of water budgets computed from NWP models and observational datasets during AMMA-EOP Type de document : Article/Communication Auteurs : Olivier Bock Editeur : American meteorological society AMS Année de publication : 2008 Projets : AMMA & AMMA-2 / Janicot, Serge Conférence : CHTM 2008, 28th Conference on Hurricanes and Tropical Meteorology 27/04/2008 02/05/2008 Orlando Floride - Etats-Unis OA Proceedings Importance : 6 p. 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] mousson
[Termes IGN] précipitation
[Termes IGN] prévision météorologique
[Termes IGN] vapeur d'eauRésumé : (auteur) Understanding the water cycle in the West African Monsoon (WAM) system is a major objective of AMMA. The water cycle is the result of the interplay of various coupled atmospheric ocean continental surface processes. The identification of the mechanisms involved and the scales at which they operate is approached here through the investigation of water budgets terms (precipitable water vapour PWV, water vapour fluxes WVF, precipitation P, and evapo-transpiration ETP). The present study focuses on the intercomparison of datasets that are currently used for the computation of such water budgets are large scale. Numerical Weather Prediction (NWP) models provide their own complete description of the water cycle but with limitations (especially in P and ETP terms). During the AMMA EOP, many additional observations went into the NWP operational analyses which might thus be of unprecedented quality. We describe here the seasonal cycles (monthly-mean and short-term variability) of PWV, WVF, P and ETP obtained from ECMWF operational analyses, as well as NCEP reanalysis 1 and 2, for years 2005 to 2007. Significant differences are seen between the different analyses, with NCEP reanalysis 1 being of much poorer quality (in term of overall bias, seasonal cycle and spatial structure). Water vapour convergence and budget closure from the different NWP datasets are also examined in several boxes over continental West Africa. There also, significant differences are found for the different analyses. The water budget estimates are also assessed comparing some terms with observational datasets (PWV from GPS, radiosondes, and satellites; P from EPSAT-SG and GPCP; ETP from land and ocean surface models). A combined water budget is computed, using NWP estimates for WVF and observation-based datasets for P and ETP. This is used to investigate the origine of the sources of water (e.g., oceanic versus continental), the significance of water recycling and atmospheric advection of water, and the link between the intra-seasonal variability in the water budget terms and the coupled atmospheric ocean continental surface processes. Numéro de notice : C2008-037 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://ams.confex.com/ams/pdfpapers/138101.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103422
