Dry Snow Metamorphism

Abstract

The goal of this project was to characterize the structural evolution of dry snow as it underwent metamorphism under either quasi-isothermal conditions or a temperature gradient, and to determine the dominant mass transport mechanism. Observational techniques involved a combination of optical microscopy, scanning electron microscopy (SEM) and X-ray computed microtomography (micro-CT). Because of its non-destructive nature, the micro-CT enabled the collection of time-series images, including the acquisition of various quantified structural parameters as porosity and specific surface area. Fine structural features and impurities in both fresh and metamorphosed snow were examined using the SEM. In addition, ice sphere arrays were studied as geometrically-simplified aggregates and it was found that while small protrusions grew to bridge the gap between adjacent ice spheres under a quasi-isothermal condition, a larger number of faceted crystals developed under a temperature gradient >100?C/m.

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Document Details

Document Type
Technical Report
Publication Date
Sep 19, 2012
Accession Number
ADA573303

Entities

People

  • Ian Baker

Organizations

  • Dartmouth College

Tags

Communities of Interest

  • Air Platforms
  • Biomedical

DTIC Thesaurus Topics

  • Chemistry
  • Crystals
  • Electron Microscopes
  • Electron Microscopy
  • Engineering
  • Geometry
  • Grain Boundaries
  • High Resolution
  • Image Processing
  • Microscopes
  • Microscopy
  • Optical Images
  • Scanning Electron Microscopy
  • Students
  • Temperature Gradients
  • Three Dimensional
  • X Rays

Readers

  • Coastal Oceanography
  • Materials Science and Engineering.
  • Polar and Arctic Studies

Technology Areas

  • Microelectronics
  • Microelectronics - Microelectromechanical Systems