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Spatial–temporal variations of water vapor content over Ethiopia: a study using GPS observations and the ECMWF model / Kibrom Ebuy Abraha in GPS solutions, vol 21 n° 1 (January 2017)  

Public [article]  inGPS solutions > vol 21 n° 1 (January 2017) . - pp 89 - 99 Titre : Spatial–temporal variations of water vapor content over Ethiopia: a study using GPS observations and the ECMWF model Type de document : Article/Communication Auteurs : Kibrom Ebuy Abraha, Auteur ; Elias Lewi, Auteur ; Frédéric Masson, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 89 - 99 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] analyse spatio-temporelle [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] Ethiopie [Termes descripteurs IGN] humidité de l'air [Termes descripteurs IGN] modèle météorologique [Termes descripteurs IGN] sécheresse [Termes descripteurs IGN] station GPS [Termes descripteurs IGN] teneur en vapeur d'eau [Termes descripteurs IGN] teneur intégrée en vapeur d'eau [Termes descripteurs IGN] variation saisonnière Résumé : (Auteur) We characterize the spatial–temporal variability of integrated water vapor (IWV) in Ethiopia from a network of global positioning system (GPS) stations and the European Center for Medium range Weather Forecasting (ECMWF) model. The IWV computed from the ECMWF model is integrated from the height of the GPS stations on 60 pressure levels to take both the actual earth surface and the model orography discrepancies into account. First, we compare the IWV estimated from GPS and from the model. The bias varies from site to site, and the correlation coefficients between the two datasets exceed 0.85 at different time scales. The results of this study show that the general ECMWF IWV trend is underestimation over highlands and overestimation over lowlands for wet periods, and overestimation over highlands and underestimation over lowlands for dry periods with very few exceptional stations. Second, we observe the spatial variation of the IWV. High values are obtained in those stations that are located in the north-eastern (Afar depression) sites and the south-western part of the country. This distribution is related to the spatial variability of the climate in Ethiopia. Finally, we study the seasonal cycle and inter-annual variability of IWV for all stations over Ethiopia. The main result is the strong inter-annual variability observed for the dry seasons. Numéro de notice : A2017-013 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article En ligne : http://dx.doi.org/10.1007/s10291-015-0508-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83935 [article]