DigitalSnow is a research project that concerns the Discrete Geometry and Applied Mathematics for Snow Metamorphism.
It is funded by the French National Research Agency (ANR-11-BS02-009) and involves 3 research laboratories: the LIRIS, the LAMA and the CEN / CNRM – GAME.
During a snowfall, the snow crystals accumulate on the ground and gradually form a complex porous medium constituted of air, water vapor, 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 general effects of theses various types of metamorphism are roughly well-known, the physical mechanisms that lead to these transformations are not perfectly well understood. A better microscale simulation of these mechanisms would help to understand how snow changes its microstructure depending on the applied physical conditions and has major impacts on the studies of snow behavior and properties at larger scale.
The main purpose of this project is to provide effi cient computational tools to study the snow metamorphism from 3D images of real snow microstructures acquired using X-ray tomography techniques. In particular, our work will focus on the development of 3D image-based numerical models that 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 justifi es the collaboration between the CEN, the LAMA and the LIRIS respectively. To achieve our objectives, three key points are required: obtaining 3D images of snow microstructures, representing the digital objects with adapted data structures in order to perform numerical measurements, and evolving the digital objects according to physical laws. Last but not least, experimental validations of the proposed tools and models are required. The project is composed of the four following tasks:
- Snow metamorphism modelling
- HP digital toolbox for volumetric and surface analysis
- Dynamic digital structures for evolving regions
- Physical rendering for snow radiative transfer
This project has several impacts in Snow Physics, Applied Mathematics and Computer Science. The main results will be made available to the scientifi c community using the DGtal open source library.
