Blanc SIMI 2 - Blanc - SIMI 2 - Science informatique et applications

Digital Geometry and Applied Mathematics for Snow Metamorphism – DigitalSnow

Submission summary

The origin of the project comes from discussion between computer scientists and researchers from CEN -
MétéoFrance working on the analysis of snow. During a snowfall, the snow crystals accumulate on the ground
and gradually form a complex porous medium constituted of air, water vapour, ice and sometimes liquid
water. This ground-lying snow transforms with time, depending on the physical parameters of the environment.
This process, called metamorphism, can be divided into three main types of metamorphisms: the wet snow
metamorphism, the isothermal metamorphism, and the temperature gradient (TG) metamorphism. In polar
or mountainous conditions, these processes are followed by compaction of snow into ice under the load of the
upper snow layers. Although the effects of theses different transformations are roughly well-known, the physical
mechanisms that lead to these transformations are not yet perfectly well understood. A better simulation of these
mechanisms would help the understanding of how the snow and ice change their microstructure depending on the
applied physical conditions. For instance, this offers interesting outcomes to forecast snow, firn and ice thermal,
mechanical and chemical properties. Furthermore, from physical parameters of snow microstructure, the
objective is to model a macro- model or even a large scale model of ground-lying behaviours. The main purpose of
this project is to provide efficient computational tools to study the snow metamorphism from 3-D images of real
snow microstructures acquired using X tomography techniques. In particular, our work will focus on the
development of 3-D image-based numerical models than can simulate the shape evolution of the snow microstructure
during its metamorphism. It will be completed by other tools designed to extract physical properties from the
computed microstructures. The resolution of these problems requires a strong interaction between three
disciplines: Snow physics, Applied Mathematics and Computer Science, which justifies the collaboration between the
CEN, the LAMA and the LIRIS respectively. To achieve our objectives, three key points are required: obtaining
3-D images of snow microstructures, representing the digital objects with adapted data structures and perform
measurements, and evolving the digital objects according to physical laws. Last but not least, an experimental
validation of the proposed tools and models are required.

Project coordinator

CNRS - DELEGATION REGIONALE RHONE-AUVERGNE (Divers public)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CNRS - DELEGATION REGIONALE RHONE-AUVERGNE
UNIVERSITE DE SAVOIE - CHAMBERY
CNRS - DELEGATION REGIONALE MIDI-PYRENEES

Help of the ANR 413,733 euros
Beginning and duration of the scientific project: August 2011 - 48 Months

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