Modèle:
Mise à jour:
4 times per day, from 00:00, 06:00, 12:00 and 18:00 UTC
Copyright:
This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF)
Source: https://www.ecmwf.int
Licence Statement:
This ECMWF data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0).
Link: https://creativecommons.org/licenses/by/4.0/

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Greenwich Mean Time:
12:00 UTC = 14:00 CEST
Résolution:
0.25° x 0.25°
Paramètre:
Maximum wind velocity of convective wind gusts
Description:
The method of Ivens (1987) is used by the forecasters at KNMI to predict the maximum wind velocity associated with heavy showers or thunderstorms. The method of Ivens is based on two multiple regression equations that were derived using about 120 summertime cases (April to September) between 1980 and 1983. The upper-air data were derived from the soundings at De Bilt, and observations of thunder by synop stations were used as an indicator of the presence of convection. The regression equations for the maximum wind velocity (wmax ) in m/s according to Ivens (1987) are:

where The amount of negative buoyancy, which is estimated in these equations by the difference of the potential wet-bulb temperature at 850 and at 500 hPa, and horizontal wind velocities at one or two fixed altitudes are used to estimate the maximum wind velocity. The effect of precipitation loading is not taken into account by the method of Ivens. (Source: KNMI)
NWP:
La prévision numérique du temps (PNT) est une application de la météorologie et de l'informatique. Elle repose sur le choix d'équations mathématiques offrant une proche approximation du comportement de l'atmosphère réelle. Ces équations sont ensuite résolues, à l'aide d'un ordinateur, pour obtenir une simulation accélérée des états futurs de l'atmosphère. Le logiciel mettant en œuvre cette simulation est appelé un modèle de prévision numérique du temps.


Prévision numérique du temps. (2009, décembre 12). Wikipédia, l'encyclopédie libre. Page consultée le 20:48, février 9, 2010 à partir de http://fr.wikipedia.org/w/index.php?title=Pr%C3%A9vision_num%C3%A9rique_du_temps&oldid=47652746.