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Global 4DVAR assimilation and forecast experiments using AMSU observations over land. Part II: Impacts of assimilating surface-sensitive channels on the African monsoon during AMMA / Fatima Karbou in Weather and Forecasting, vol 25 n° 1 (February 2010)    

Public [article]  inWeather and Forecasting > vol 25 n° 1 (February 2010) . - pp Titre : Global 4DVAR assimilation and forecast experiments using AMSU observations over land. Part II: Impacts of assimilating surface-sensitive channels on the African monsoon during AMMA Type de document : Article/Communication Auteurs : Fatima Karbou, Auteur ; Florence Rabier, Auteur ; Jean-Philippe Lafore, Auteur ; Jean-Luc Redelsperger, Auteur ; Olivier Bock , Auteur Année de publication : 2010 Projets : AMMA & AMMA-2 / Janicot, Serge Article en page(s) : pp Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Afrique occidentale [Termes IGN] assimilation des données [Termes IGN] coordonnées GPS [Termes IGN] données météorologiques [Termes IGN] emissivité [Termes IGN] étude de faisabilité [Termes IGN] humidité de l'air [Termes IGN] image NOAA-AMSU [Termes IGN] mousson [Termes IGN] prévision météorologique Résumé : (auteur) Observations from Advanced Microwave Sounding Unit-A and -B (AMSU-A and -B) have been more intensively used over sea than over land because of large uncertainties about the land surface emissivity and the skin temperature. Several methods based on a direct estimation of the land emissivity from satellite observations have been found to be very useful for improving the assimilation of sounding channels over land. Feasibility studies have been conducted within the Météo-France global assimilation system in order to examine the possibility of assimilating low-level atmospheric observations receiving a contribution from the land surface. The present study reports on three 2-month assimilation and forecast experiments, which include the assimilation of surface-sensitive observations from AMSU-A and -B together with a control experiment, which represents the operational model. The assimilation experiments have been compared with the control, and important changes in the analyzed atmospheric fields and in the precipitation forecasts over parts of the tropics, and especially over West Africa, have been noticed. The experiments seem to emphasize the atmospheric moistening in India, South America, and in West Africa, together with atmospheric drying over Saudi Arabia and northeast Africa. The drying or moistening of the atmosphere has been successfully evaluated using independent measurements from the GPS African Monsoon Multidisciplinary Analysis (AMMA) network. Precipitation and OLR forecasts have also been examined and compared with independent measurements. Physically, the changes result in a better-organized African monsoon with a stronger ITCZ in terms of ascent, vorticity, and precipitation, but there is no northward shift of the monsoon system. Low-level humidity observations have been found to have important impacts on the analysis and to produce positive impacts on forecast scores over the tropics. Numéro de notice : A2010-664 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1175/2009WAF2222244.1 Date de publication en ligne : 01/02/2010 En ligne : https://doi.org/10.1175/2009WAF2222244.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91770 [article]

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Microwave land emissivity calculations using AMSU measurements / Fatima Karbou in IEEE Transactions on geoscience and remote sensing, vol 43 n° 5 (May 2005)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 43 n° 5 (May 2005) . - pp 948 - 959 Titre : Microwave land emissivity calculations using AMSU measurements Type de document : Article/Communication Auteurs : Fatima Karbou, Auteur ; C. Prigent, Auteur Année de publication : 2005 Article en page(s) : pp 948 - 959 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] Advanced Microwave Sounding Unit [Termes IGN] emissivité [Termes IGN] image DMSP-SSM/I [Termes IGN] image NOAA-AMSU [Termes IGN] surface du sol [Termes IGN] télédétection en hyperfréquence Résumé : (Auteur) Atmospheric parameter retrievals over land from Advanced Microwave Sounding Unit (AMSU) measurements, such as atmospheric temperature and moisture profiles, could be possible using a reliable estimate of the land emissivity. The land surface emissivities have been calculated using six months of data, for 30 beam positions (observation zenith angles from 58° to +58°) and the 23.8-, 31.4-, 50.3-, 89-, and 150-GHz channels. The emissivity calculation covers a large area including Africa, Eurasia, and Eastern South America. The day-to-day variability of the emissivity is less than 2% in these channels. The angular and spectral dependence of the emissivity is studied. The obtained AMSU emissivities are in good agreement with the previously derived SSMI ones. The scan asymmetry problem has been evidenced for AMSU-A channels. And possible extrapolation of the emissivity from window channels to sounding ones has been successfully tested. Numéro de notice : A2005-214 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.837503 En ligne : https://doi.org/10.1109/TGRS.2004.837503 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27351 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-05051	RAB	Revue	Centre de documentation	En réserve L003	Disponible

NOAA operational hydrological products derived from the Advanced Microwave Sounding Unit / R.R. Ferraro in IEEE Transactions on geoscience and remote sensing, vol 43 n° 5 (May 2005)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 43 n° 5 (May 2005) . - pp 1036 - 1049 Titre : NOAA operational hydrological products derived from the Advanced Microwave Sounding Unit Type de document : Article/Communication Auteurs : R.R. Ferraro, Auteur ; F. Weng, Auteur ; N.C. Grody, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 1036 - 1049 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] données hydrographiques [Termes IGN] données météorologiques [Termes IGN] hyperfréquence [Termes IGN] image Aqua-AMSR [Termes IGN] image NOAA-AMSU [Termes IGN] surveillance météorologique Résumé : (Auteur) With the launch of the NOAA-15 satellite in May 1998, a new generation of passive microwave sounders was initiated. The Advanced Microwave Sounding Unit (AMSU), with 20 channels spanning the frequency range from 23-183 GHz, offers enhanced temperature and moisture sounding capability well beyond its predecessor, the Microwave Sounding Unit (MSU). In addition, by utilizing a number of window channels on the AMSU, the National Oceanic and Atmospheric Administration (NOAA) expanded the capability of the AMSU beyond the original purpose and developed a new suite of products that tare generated through the Microwave Surface and Precipitation Products System (MSPPS). This includes precipitation rate, total precipitable water, land surface emissivity, and snow cover. Details on the current status of the retrieval algorithms (as of September 2004) are presented. These products are complimentary to similar products obtained from the Defense Meteorological Satellite Program Special Sensor Microwave/Imager (SSMI) and the Earth Observing Aqua Advanced Microwave Scanning Radiometer (AMSR-E). Due to the close orbital equatorial crossing time between NOAA-16 and the Aqua satellites, comparisons between several of the MSPPS products are made with AMSR-E. Finally, several application examples are presented that demonstrate their importance to weather forecasting and analysis, and climate monitoring. Numéro de notice : A2005-215 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.843249 En ligne : https://doi.org/10.1109/TGRS.2004.843249 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27352 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-05051	RAB	Revue	Centre de documentation	En réserve L003	Disponible