Snowpack monitoring with upward-looking radar systems towards improved avalanche risk prediction

雪板雪崩是指在一个延伸的薄弱面上有粘性的雪板的释放。雪地层学的现场观测是必要的可靠预测雪坡的不稳定性，传统上从破坏性的方法在雪坑。这阻碍了获取有关积雪演变的信息，并经常使调查人员面临雪崩风险。因此，在高不稳定时期的边坡现场信息很少得到。该项目研究、采用和推进遥控上视雷达系统的应用，以非破坏性方式对积雪的当地物理特性进行成像和分析，并将其同化到积雪演变的现有模型中。雷达安装在积雪下，随着积雪高度的增加而被掩埋。由于积雪中的薄弱层具有与其周围环境不同的结构或物理特性，因此向上穿过积雪的透射波被部分反射。对雷达接收到的反射波进行分析，得出积雪的物理特性（内部层数和性质、雪厚、密度）。每天重复进行这种测量，可以准实时和无破坏地监测积雪地层的发展情况，并同时提供信息，以估计雪崩的危险。该项目为在潜在不稳定的斜坡上自主监测积雪地层学提供了第一步，而不会给调查人员带来风险。

Snow slab avalanches involve the release of a cohesive slab over an extended plane of weakness. In-situ observations of snow stratigraphy are necessary for reliable prediction of snow-slope instability, conventionally obtained from destructive methods in snow pits. This hampers acquiring information about temporal snowpack evolution and often exposes the investigator to avalanche risk. Therefore, in-situ information from slopes during high-instability periods are seldom obtained. This project investigates, employs and advances the application of remotely operated upward-looking radar systems to non-destructively image and characterise the local physical properties of the snowpack, and assimilation thereof into an existing model of snowpack evolution. The radar is mounted underneath the snowpack and buried with increasing snow height. As weak layers in the snowpack have different structure or physical properties than their surroundings, transmitted waves traveling upwards through the snowpack are partially reflected. Analyses of reflected waves received by the radar yield a physical characterisation of the snowpack (internal layer number and properties, snow thickness, density). Repetition of such measurements on a daily basis allows for quasi real-time and destruction free monitoring of the development of snowpack stratigraphy and concurrent information to estimate avalanche danger. This project provides an initial step for autonomous monitoring of snow stratigraphy also in potentially unstable slopes without risks for the investigators.