Passy database

wintertime atmospheric dynamics and air quality in a narrow alpine valley

The Passy-2015 field experiment

Wintertime anticyclonic conditions are often associated to high levels of pollution in urbanized or industrialized area, particularly in mountainous terrain.

The Arve river valley is very sensitive to this phenomenon, in particular close to the city of Passy (Haute-Savoie), 20 km down valley past Chamonix. The area has indeed one of the worst air quality in France.
Besides air quality monitoring, as managed by the local air quality agency Air Rhône-Alpes or the project DECOMBIO led by LGGE, it is crucial to improve our understanding of atmospheric dynamics within the valley under these wintertime conditions in order to know how it drives pollutants dispersion.

This is why the Passy-2015 field experiment was carried out in this area during the winter 2014-2015. A quite large number of instruments (wind, temperature and water vapor profilers, scanning lidars, instrumented towers…) were deployed on a main site and four satellite sites. In February 2015, during two intensive observation periods, high frequency radiosondes, a tethered balloon, a UAV and a sodar were added.

Several years of collaborative work by scientists and engineers from Air Rhône-Alpes, CNRM, LEGI, LGGE, LTHE and NCAS (UK) will follow this field experiment.

The Passy-2015 field experiment was supported by ADEME through the French national programme LEFE/INSU and by METEO FRANCE. We thank the cities of Passy and Sallanches for their kind support. The field experiment was led by CNRM while LEGI is the principal investigator of the LEFE/INSU project.