A METHOD FOR THE FORECASTING OF WIND IN MOUNTAINOUS REGIONS.

ABSTRACT: To forecast blowing snow in mountainous regions one needs precise information on the velocity and direction of the wind. In order to reach this objective, we have developed a statistical application (VENTOSE) for the fOIe-casting of wind parameters at ground level by using as long as possible series of data. These data are collected by automatic measurements in a high altitude location (Col du Lac Blanc in the French Alps, alt. 2800 m-) which is exposed to strong winds during the winter season. This experimental site has been well equipped for studies of snowdrift. For this study, various atmospheric parameters from the ECMWF (European Centre for Medium range Weather Forecast) data archives have been extracted and statistical relationships between these parameters and wind measurements at the site have been established. A multi-linear method was used to calculate equations in order to estimate the wind velocity and the wind direction for the follONing day. The comparison between observed and forecast wind done with this method was calculated in the same location during a winter period not included in the learning file. In most cases, wind velocity is well estimated (correlation coefficient equal to 0.77). In the framework of a joint research project with the VI (Icelandic Meteorological Office) that started in 1997, we have tested this method in Icelandic locations. The project has been initiated in order to enhance the exchange of expertise between VI and Meteo-France in research on snowdrift and a\6-lanche hazard. The testing phase will take place in Iceland where simulated snowdrift will be compared to observations. The method and the results of this study will be shown and discussed in the presentation