Numerical Forecasting Of Nocturnal Fog: Validation Through Experimental Data. Application To Pollution Problem.

We present a method of nocturnal fog forecast based on a one-dimensional numerical model forced by mesoscale parameters provided by the forecasts of the French operational model PERIDOT. The "columnar" model, called COBEL, finely restitutes the evolution of the nocturnal atmospheric layer (surface cooling, formation of the nocturnal inversion, wind vertical profile, dew deposition,...). It also simulates the formation and the evolution of a fog layer (fog depth, liquid water content, horizontal visibility). The validation of this model is performed using data obtained during a field experiment. This model, forced by mesoscale parameters (horizontal advection, geostrophic wind and cloud cover) can be used for nocturnal layer and fog forecasting over a given site. A validation is presented from forcing of the meteorological model PERIDOT. Finally, the last section is devoted to a discussion on the possible uses of this model coupled to local or regional scale on pollution problems