Blowing snow sublimation at high altitude and effects on the surface boundary layer,
Vionnet, V. ; Guyomarc'h, G. ; Deliot, Y. ; Naaim Bouvet, F. ; Sicart, J.E. ; Bellot, H. ; Merzisen, H.
Type de document
Communication scientifique sans actes
Affiliation de l'auteur
METEO FRANCE CNRS UMR 3589 CNRM GRENOBLE FRA ; METEO FRANCE CNRS UMR 3589 CNRM GRENOBLE FRA ; METEO FRANCE CNRS UMR 3589 CNRM GRENOBLE FRA ; IRSTEA GRENOBLE UR ETGR FRA ; IRD CNRS-INSU UNIVERSITE GRENOBLE ALPES GRENOBLE INP UMR 5001 INSTITUT DES GEOSCIENCES DE L'ENVIRONNEMENT GRENOBLE FRA ; IRSTEA GRENOBLE UR ETGR FRA ; METEO FRANCE CNRS UMR 3589 CNRM GRENOBLE FRA
Résumé / Abstract
In alpine terrain, wind-induced snow transport strongly influences the spatial and temporal variability of the snow cover. During their transport, blown snow particles undergo sublimation with an intensity depending on atmospheric conditions (air temperature and humidity). The mass loss due to blowing snow sublimation is a source of uncertainty for the mass balance of the alpine snowpack. Additionally, blowing snow sublimation modifies humidity and temperature in the surface boundary layer. To better quantify these effects in alpine terrain, a dedicated measurement setup has been deployed at the experimental site of Col du Lac Blanc (2720 m a.s.l., French Alps, Cryobs-Clim network) since winter 2015/2016. It consists in three vertical masts measuring the near-surface vertical profiles (0.2-5 m) of wind speed, air temperature and humidity and blowing snow fluxes and size distribution. Observations collected during blowing snow events without concurrent snowfall show only a slight increase in relative humidity (10-20%) and near-surface saturation is never observed. Estimation of blowing snow sublimation rates are then obtained from these measurements. They range between 0 and 5 mmSWE day-1 for blowing snow events without snowfall in agreement with previous studies in different environments (North American prairies, Antarctica). Finally, an estimation of the mass loss due to blowing snow sublimation at our experimental site is proposed for two consecutive winters. Future use of the database collected in this study includes the evaluation of blowing snow models in alpine terrain.
American Geophysical Union, Fall Meeting 2017, 15/12/2017 - 17/12/2017, New Orleans, USA