Das Projekt "High Resolution Radar Imaging of Snow Avalanches" wird vom Umweltbundesamt gefördert und von Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft durchgeführt. Geophysical mass flows, such as snow avalanches, are a major hazard in mountainous areas and have a significant impact on the infrastructure, economy and tourism of such regions. Obtaining a thorough understanding of the dynamics of snow avalanches is crucial for the development of numerical models for hazard mapping and for the development of design criteria for infrastructure so that it can withstand avalanche impact. The aim of this project is to study the dynamics of mixed avalanches with the aid of an advanced Frequency Modulated Continuous Wave (FMCW), phased array, radar that provides high resolution 2-D animated imaging and velocity data of the avalanche dense core (Ash et al., 2010, 2011a, Vriend et al., 2012). The instrument to be used in this project improves over early instruments to study geophysical flows by two orders of magnitude in range resolution as well as having other advantages. In particular it is a phased array system with eight receive channels and therefore enables two-dimensional imaging over the whole slope as well as direct calculation of velocities using the Doppler effect. The down-slope resolution is approximately 0.75m compared to 25-50m for previous instruments and the cross slope resolution is approximately 8m. This means that the observations can be directly related to those from other sensors at the Vallée de la Sionne (VDLS) avalanche test site, where the radar is installed. These other observations include air pressure, velocity and density (Kern et al., 2009, Sovilla et al., 2008a). The synergy gained by combing all these observations has the capability to transform our understanding of a whole class of environmental mass flows; not just avalanches but also pyroclastic flows that contain similar physics. By being able to follow flow features over the whole track we expect the radar data to be of major importance in validating existing theories and developing improved avalanche models. The proposal has four components. The first is minor improvements and maintenance of the radar hardware. The second is to implement improved algorithms for the data analysis to gain the maximum resolution over the entire slope. The third is to analyze the radar data in conjunction with other data collected at the VDLS such as velocity or density profiles to gain new insight into the constitutive law of snow avalanches and to asses the relevance for the flow of specific processes such as surge formation or flow regime separation. The fourth is to test the validity of different avalanche flow models, either in terms of excluding certain constitutive relations, or by constraining parameter values. usw.