Abstract : 3K.4
Forecasting of road surface characteristics in France

Ludovic Bouilloud, Eric Martin, Patrick Lemoigne, Mario Marchetti, Jean Livet, Joel Noilhan, Florence Habets, Laurent Franchisteguy, Paul Pettré, Sophie Morel, Aaron Boone, Alain Foidart
GAME/CNRM (Météo-France, CNRS)

During winter, ice or snow presence on the road might have serious consequences on road traffic. To develop a decision-making tool for road management in winter, a numerical model which permits to simulate snow behaviour on roads was developed. It results from the coupling of the ISBA and CROCUS models, which are respectively the soil and snow model of Météo-France, and beforehand adapted to the road problematic. The developed model permits to consider the variability of snow/road interface types, and consequently the variability of heat and water transfer associated. This model was validated thanks to observed snow on road events, resulting from a previous experimental field campaign led on the Météo-France experimental station located at the Col de Porte (1320m, French Alps), where experimental pavements were built for the needs of the project. The validation was first done with the meteorological data measured on the site, and then with forecasted data of the SAFRAN model. Results of the forecast on the experimental site were satisfactory, with a detection of the majority of snow presence on the experimental pavement, and an accurate forecast of the road surface temperature evolution. So, the model was spatialized at the France scale, with a 8km grid resolution, corresponding to the SAFRAN model France scale. The 2004/05 winter, with many snow on road events, was simulated. The validation was done thanks to road station data from several Highways and thanks to measurement from the Météo-France stations network. Results were encouraging and permitted to consider an operational use for the model.