Dust motion in snow microstructure

The deposition of light-absorbing particles (LAPs) such as mineral dust and black carbon on snow is responsible for a highly effective climate forcing, through darkening of the snow surface and associated feedbacks. The interplay between post-depositional snow transformation (metamorphism) and the dynamics of LAPs in snow remains largely unknown. We obtained time series of X-ray tomography images of dust-contaminated samples undergoing dry snow metamorphism around -2°C. They provide the first observational evidence that temperature gradient metamorphism induces dust particle motion in snow, while no movement is observed under isothermal conditions. Under temperature gradient metamorphism, dust particles can enter the ice matrix due to sublimation-condensation processes and spread down mainly by falling into the pore space. Overall, such motions might reduce the radiative impact of dust in snow, in particular in arctic regions where temperature gradient metamorphism prevails.

Details on the data can be found in the associated paper (Hagenmuller et al., 2019).

The dataset contains: - 1_3D_Microstructure/Sample_[XX]t[YY]h.mhd : segmented 3D image of the snow and dust microstructure of sample XX (ISO: sample undergoing isothermal metamorphism, TG: sample undergoing temperature-gradient metamorphism) at different times YY from the experiment start. Image format according to: https://itk.org/Wiki/ITK/MetaIO/Documentation. See Fig. 1 in the associated paper. - 2_Microstructural_Evolution_Sample_[XX].txt : ASCII file describing the time evolution of the density, specific surface area and anisotropy of sample XX. See Fig. 2 in the associated paper. - 3_Ice-Dust_Contact_Distribution_Sample_[XX].txt: ASCII file describing the distribution of the ice-dust contact of sample XX at different times. See Fig. 3 in the associated paper. - 3_Ice-Dust_Contact_Evolution_Sample_[XX].txt: ASCII file describing the time evolution of the ice-dust contact area of sample XX. See Fig. 3 in the associated paper. - 4_Vertical_Displacement_Evolution_Sample_[XX].txt : ASCII file describing the time evolution of the vertical position of dust particles and ice for sample XX. See Fig. 4 in the associated paper. - 4_Vertical_Speed_Distribution_Sample_[XX].txt : ASCII file describing the distribution of the vertical speed of dust particles and ice for sample XX at different times. See Fig. 4 in the associated paper. - 5_Vertical_Speed_AsAFunctionOf_Ice-Dust_Contact_Sample_TG.txt : ASCII file describing the vertical speed of dust particles as a function of the ice-dust contact for sample TG. See Fig. 5 in the associated paper. - 6_Vertical_Speed_AsAFunctionOf_Particle_Size_Sample_TG.txt : ASCII file describing the vertical speed of dust particles as a function of particle size for sample TG. See Fig. A3 in the associated paper.