Cryobs-Clim-CLB / Col du Lac Blanc : a meteorological and blowing snow observatory

The Col du Lac Blanc observatory is located near l'Alpe d'Huez resort in the Grandes-Rousses massif and is dedicated to study interactions between the cryosphere and the atmosphere at high altitude, with a focus on blowing and drifting snow studies. The site is managed by Météo-France (CNRM/CEN) and IRSTEA (Université Grenoble Alpes). It comprises four stations: Lac Blanc (CRYOBSCLIM.CLB.LACBLANC), La Muzelle (CRYOBSCLIM.CLB.LAMUZELLE), Dome (CRYOBSCLIM.CLB.DOME) and Col (CRYOBSCLIM.CLB.COL). This data is complemented by dataset containing information on hourly blowing snow occurrence relying on an empirical method at Col du Lac Blanc (CRYOBSCLIM.CLB.BSO) and continuous hourly meteorological output of the SAFRAN meteorological analysis system (CRYOBSCLIM.CLB.SAFRAN).The Digital Elevation Model of the study area (1,5 km²) at 1-m resolution is also provided in RGF 93 Lambert 93 coordinates (CRYOBSCLIM.CLB.DEM). The pass orientation and the specific configuration of the surrounding summits make it closely resemble a natural wind tunnel. The north–south direction accounts for 90% of the wind directions. Aeolian snow transport is observed 10% of the time in winter and occurs with concurrent snowfall 37% of the time (Vionnet et al. 2013). The experimental site and related instrumentation are described in details in Guyomarc’h et al. (2018). Available data acquired during winter seasons include wind speed and direction, drifting snow fluxes, snow height, air temperature. Humidity, precipitation, incoming shortwave and longwave radiation from reanalysis are also included. Data have been used to evaluate and develop physical parameterizations of blowing and drifting snow in alpine terrain. Snowpack models and atmospheric models simulating wind-induced snow transport have also been evaluated at this site. Finally, Col du Lac Blanc is a target site to evaluate Numerical Weather Prediction (NWP) models in alpine terrain. Cryobs-Clim-CLB is a Cryonet site of Global Cryosphere Watch (WMO), a member of the International Network for Alpine Research Catchment Hydrology (INARCH) and a part of OZCAR Infrastructure.