Measuring Snow Profiles with High Resolution: Interpretation of the Force-distance Signal from a Snow Micro Penetrometer

The classification of snow profiles is traditionally based on the discrete interpretation of snow layers in a snow pack. The layers are discriminated according to the physical properties of the snow. To account for the micro-mechanical behaviour of snow in deformation, the classification needs to be extended to the micro-structure of snow. A new instrument, the high-resolution snow penetrometer "SnowMicroPen" has been introduced. It is a new instrument to continuously measure the snow hardness at the micro-scale. The new method of snow interpretation is described. Different quantitative approaches to interpret the penetrometer force-distance signal are shown. The penetrometer force signal reveals the great variability of the microand meso-properties in a snow pack. A comparison of the physical characterization of snow and the new, mechancial characterization is shown. Being able to measure the complexity of the micro-properties of snow is the basis for a snow classification that includes the deformational behaviour of snow. It is also the basis to investigate scale and spatial variability questions.