Analysis of Near-Surface Atmospheric Variables: Validation of the SAFRAN Analysis over France

Abstract : Système d'analyse fournissant des renseignements atmosphériques à la neige (SAFRAN) is a mesoscale atmospheric analysis system for surface variables. It produces an analysis at the hourly time step using ground data observations. One of SAFRAN's main features is that it is based on climatically homogeneous zones and is able to take vertical variations into account. Originally intended for mountainous areas, it was later extended to cover France. This paper focuses on the validation of the extended version. The principle of the analysis is described and its quality was tested for five parameters (air temperature, humidity, wind speed, rainfall, and incoming radiation), using Météo-France's observation network and data of some well-instrumented stations. Moreover, SAFRAN's rainfall was compared with another analysis, known as analyse utilisant le relief pour l'hydrométéorologie (Aurelhy). Last, two different versions of SAFRAN were compared for mountain conditions. Temperature and relative humidity were well reproduced, presenting no bias. Wind speed was also well reproduced; however, its bias was - 0.3 m s–1. The interpolation from the 6-h time step of the analysis to the 1h time step was one of the sources of error. The precipitation analysis was robust and not biased; its root-mean-square error was 2.4 mm day-1. This error was mainly due to the spatial heterogeneity of the precipitation within the geographical zones of analysis (1000 km2). The analysis of incoming solar radiation presented some biases, especially in coastal areas. The results of the comparison with some well-instrumented sites were encouraging. SAFRAN is being run operationally at Météo-France on a real-time basis for various applications.
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Journal of Applied Meteorology and Climatology, American Meteorological Society, 2008, 47, pp.92-107. 〈10.1175/2007JAMC1636.1〉
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https://hal-meteofrance.archives-ouvertes.fr/meteo-00259825
Contributeur : Eric Martin <>
Soumis le : vendredi 29 février 2008 - 14:39:05
Dernière modification le : jeudi 11 janvier 2018 - 06:23:26

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Pere Quintana Seguí, P. Le Moigne, Yves Durand, Eric Martin, Florence Habets, et al.. Analysis of Near-Surface Atmospheric Variables: Validation of the SAFRAN Analysis over France. Journal of Applied Meteorology and Climatology, American Meteorological Society, 2008, 47, pp.92-107. 〈10.1175/2007JAMC1636.1〉. 〈meteo-00259825〉

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