Effects of firn ventilation on geochemistry of polar snow
Thesis (Ph. D.)--University of Washington, 2003 The effects of air motion in firn on geochemical species is examined. Stable isotope data from Taylor Mouth, Antarctica are compared with data from nearby Taylor Dome and are found to be significantly different. Three possible reasons for the differenc...
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ftunivwashington:oai:digital.lib.washington.edu:1773/6800 2024-06-02T07:55:26+00:00 Effects of firn ventilation on geochemistry of polar snow Neumann, Thomas A., 1973- 2003 xi, 223 p. http://hdl.handle.net/1773/6800 en_US eng b50376470 53950106 Thesis 52669 http://hdl.handle.net/1773/6800 Copyright is held by the individual authors. Theses--Geophysics Thesis 2003 ftunivwashington 2024-05-06T11:38:24Z Thesis (Ph. D.)--University of Washington, 2003 The effects of air motion in firn on geochemical species is examined. Stable isotope data from Taylor Mouth, Antarctica are compared with data from nearby Taylor Dome and are found to be significantly different. Three possible reasons for the difference between these two records are presented: (1) the standard stable isotope - surface temperature relationship, (2) mixing precipitation from several sources and (3) post-depositional isotopic change.A two-dimensional model to estimate condensation and sublimation rates of water in firn based on firn-ventilation theory is presented. This model is used to investigate preservation characteristics of chemical species in snow and quantify the effects of post-depositional water-vapor motion. Results demonstrate the sensitivity of sublimation and condensation rates in the firn to hand-to-hand diffusion, grain size, wind speed and temperature.The sensitivity of stable isotope ratios to firn ventilation quantify what other investigators have suggested: isotopic exchange in the upper few meters is more rapid than can be explained by existing models, isotopic equilibration with atmospheric vapor is an important component of isotopic exchange and ventilation enhances exchange by creating regions of relatively rapid sublimation and condensation in the firn.The concentration of irreversibly deposited species (e.g. non-sea-salt-sulfate) is decreased by condensation in pore spaces and increased by sublimation of surrounding ice grains. Results suggest that concentration changes induced by firn ventilation are on the order of 3%, making it unlikely that this effect can be detected in field data.The concentration of reversibly-deposited species in snow (e.g. H 2O2) is generally decreased by sublimation of the surrounding ice grain. Condensation increases the diffusion path from the grain interior to the surface and can scavenge species which exist as trace gasses from pore-space air. Results suggest that firn ventilation has little ... Thesis Antarc* Antarctica University of Washington, Seattle: ResearchWorks Taylor Dome ENVELOPE(157.667,157.667,-77.667,-77.667) |
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Open Polar |
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University of Washington, Seattle: ResearchWorks |
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ftunivwashington |
language |
English |
topic |
Theses--Geophysics |
spellingShingle |
Theses--Geophysics Neumann, Thomas A., 1973- Effects of firn ventilation on geochemistry of polar snow |
topic_facet |
Theses--Geophysics |
description |
Thesis (Ph. D.)--University of Washington, 2003 The effects of air motion in firn on geochemical species is examined. Stable isotope data from Taylor Mouth, Antarctica are compared with data from nearby Taylor Dome and are found to be significantly different. Three possible reasons for the difference between these two records are presented: (1) the standard stable isotope - surface temperature relationship, (2) mixing precipitation from several sources and (3) post-depositional isotopic change.A two-dimensional model to estimate condensation and sublimation rates of water in firn based on firn-ventilation theory is presented. This model is used to investigate preservation characteristics of chemical species in snow and quantify the effects of post-depositional water-vapor motion. Results demonstrate the sensitivity of sublimation and condensation rates in the firn to hand-to-hand diffusion, grain size, wind speed and temperature.The sensitivity of stable isotope ratios to firn ventilation quantify what other investigators have suggested: isotopic exchange in the upper few meters is more rapid than can be explained by existing models, isotopic equilibration with atmospheric vapor is an important component of isotopic exchange and ventilation enhances exchange by creating regions of relatively rapid sublimation and condensation in the firn.The concentration of irreversibly deposited species (e.g. non-sea-salt-sulfate) is decreased by condensation in pore spaces and increased by sublimation of surrounding ice grains. Results suggest that concentration changes induced by firn ventilation are on the order of 3%, making it unlikely that this effect can be detected in field data.The concentration of reversibly-deposited species in snow (e.g. H 2O2) is generally decreased by sublimation of the surrounding ice grain. Condensation increases the diffusion path from the grain interior to the surface and can scavenge species which exist as trace gasses from pore-space air. Results suggest that firn ventilation has little ... |
format |
Thesis |
author |
Neumann, Thomas A., 1973- |
author_facet |
Neumann, Thomas A., 1973- |
author_sort |
Neumann, Thomas A., 1973- |
title |
Effects of firn ventilation on geochemistry of polar snow |
title_short |
Effects of firn ventilation on geochemistry of polar snow |
title_full |
Effects of firn ventilation on geochemistry of polar snow |
title_fullStr |
Effects of firn ventilation on geochemistry of polar snow |
title_full_unstemmed |
Effects of firn ventilation on geochemistry of polar snow |
title_sort |
effects of firn ventilation on geochemistry of polar snow |
publishDate |
2003 |
url |
http://hdl.handle.net/1773/6800 |
long_lat |
ENVELOPE(157.667,157.667,-77.667,-77.667) |
geographic |
Taylor Dome |
geographic_facet |
Taylor Dome |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
b50376470 53950106 Thesis 52669 http://hdl.handle.net/1773/6800 |
op_rights |
Copyright is held by the individual authors. |
_version_ |
1800748763304689664 |