Ice physical properties
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Ice physical properties |
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| For snow and ice there is a strong
relationship between physical properties and optical
properties. Because of this, we carried out measurements to
understand how this relationship varies with ice type and how it changes
as the ice pack evolves during the spring and summer. Because of its
large impact on albedo, particular attention
was paid to the physical properties of the surface layer. A 10-cm diameter fiberglass-barrel corer was used to take
cores from the ice.
These cores were analyzed to document vertical variations in
crystal structure, temperature, salinity, density, brine and air volumes,
and particle content. The cores were cut into
5-cm or 10-cm segments and transferred into
sealed plastic containers at the site to minimize brine drainage. Density
and salinity were measured from these segments and thin sections were prepared to determine
crystal type, size and orientation. The number and size distribution of
inclusions will be determined from image analysis of thin section photographs.
Salinities of melted samples have been derived
from electrolytical conductivity measurements conducted with a YSI model
30 conductivity sonde (measurement error
<0.02 or <1% of the bulk salinity, whichever is larger). Some melted core samples were transferred into glass
bottles for measurements of delta-18-O at the Stable Isotope Laboratory, Dept. of Physics and Astronomy, University
of Calgary, Calgary, Canada (Dr. H. R. Krouse, Dr. S. Taylor).
Stable-isotope measurements were performed on a VG 903 mass spectrometer
(carbon dioxide equilibration, measured against VSMOW) at a precision of
better than 0.4 ppt.
Below: Varied surface conditions for melting ice |
Core from top meter of multiyear ice. Note the top 30 cm. |
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Surface scattering layer scraped off, 14 July 1998. |
Self-renewing surface scattering layer, 15 July 1998. |
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