Studies of the spatial variability of alpine snowfall using an X-band polarimetric radar

A mobile polarimetric X-band radar (MXPol) was deployed in Davos, Switzerland in collaboration with SLF (WSL - Institute for Snow and Avalanche Research). MXPol was installed in the beginning of October 2009 and collected valuable and continuous information of the winter seasons of 2009/2010 and 2010/2011. Additionally, local measurements of snow accumulation on the ground were made using two Airborne Laser-Scanning (ALS) and Terrestrial Laser (TLS). The present work focuses on the Wannengrat area where the measurements were collocated. This configuration makes possible the comparison of the variability of snowfall (as seen by the radar) and in snow accumulation (from laser scans) over the entire winter seasons. A better understanding of these variabilities is a key step to improve snow pack modeling for water resources and avalanche prediction. Several sub-domains related to the topography and wind pattern are considered. The seasonal spatial structure of snowfall is analyzed and its variability from event to event as well. The differences between the spatial variability of snowfall (a few hundred meters above ground level) seen by the radar and the spatial variability in snow accumulation indicate that there are other processes involved in snow distribution (ie. transport by wind), taking place very close or at the ground level.