Dry Snow Metamorphism

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 micros...

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Bibliographic Details
Main Author: Baker, Ian
Other Authors: DARTMOUTH COLL HANOVER NH OFFICE OF GRANTS AND CONTRACTS
Format: Text
Language:English
Published: 2012
Subjects:
Snow
Ice and Permafrost
Electrooptical and Optoelectronic Devices
Test Facilities
Equipment and Methods
*METAMORPHOSIS
*SCANNING ELECTRON MICROSCOPY
*SNOW
*TEMPERATURE GRADIENTS
ACQUISITION
ARRAYS
CRYSTALS
DRY MATERIALS
ELECTRON MICROSCOPY
EVOLUTION(GENERAL)
ICE
IMAGES
IMPURITIES
NONDESTRUCTIVE TESTING
PARAMETERS
POROSITY
STRUCTURAL PROPERTIES
SURFACES
PE611102A
Ice
permafrost
Online Access:http://www.dtic.mil/docs/citations/ADA573303
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA573303
Description
Summary: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. The original document contains color images.

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