Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations
Stable water isotope ratios (18O and D) in snow pit (Juneau Icefield) and fresh snow (Eclipse Icefield) samples are included in a compilation of all available snow isotope data from coastal Alaska, and used to evaluate observed isotope shifts in regional paleoclimate records. I compiled existing iso...
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ftmaineuniv:oai:digitalcommons.library.umaine.edu:honors-1123 2023-06-11T04:12:43+02:00 Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations Koehler, Matthew C. 2013-05-01T07:00:00Z application/pdf https://digitalcommons.library.umaine.edu/honors/125 https://digitalcommons.library.umaine.edu/context/honors/article/1123/viewcontent/Koehler_Thesis.pdf unknown DigitalCommons@UMaine https://digitalcommons.library.umaine.edu/honors/125 https://digitalcommons.library.umaine.edu/context/honors/article/1123/viewcontent/Koehler_Thesis.pdf Honors College surface snow coastal northeast pacific paleoclimate interpretations δ18O Earth Sciences Environmental Sciences text 2013 ftmaineuniv 2023-05-04T18:01:52Z Stable water isotope ratios (18O and D) in snow pit (Juneau Icefield) and fresh snow (Eclipse Icefield) samples are included in a compilation of all available snow isotope data from coastal Alaska, and used to evaluate observed isotope shifts in regional paleoclimate records. I compiled existing isotope data in coastal Alaska (primarily the Saint Elias Range) in order to better understand the elevation dependence of stable atmospheric water isotope ratios in the region. The values that make up the compilation are reflective of multiple fractionation regimes associated with synoptic scale cyclonic events, described using the Cyclone-Water Isotope Model (Holdsworth and Krouse 2002). Using this Cyclone-Water Isotope Model as a link between high frequency spatial and temporal variability, fresh snow data characterizing five different events within a 17 day time span from the Eclipse Icefield were analyzed for δ18O values. Average isotope values among these five events vary by as much as 8‰. Meteorological conditions over the domain are investigated with NCEP Climate Forecast System Reanalysis (CFSR), and show that events with more depleted δ18O are associated with systems that have higher pressure and a zonal (northern) moisture source, whereas events with less depleted δ18O are related to events with lower pressure and a more significant component of southern moisture. These observations of event-based meteorological controls on δ18O variability shed light on paleoclimate interpretations of shifts in the isotopic record seen in the Mount Logan ice core and Jellybean Lake sediment core at around A.D. 800 and A.D. 1840. The findings in the paper support Fields et al. (2010) in the interpretation that the shift to lower δ18O values seen in the isotopic record is caused by a transition to a more zonal (northern) moisture source paradigm. Text ice core Alaska The University of Maine: DigitalCommons@UMaine Holdsworth ENVELOPE(166.583,166.583,-72.133,-72.133) Juneau Icefield ENVELOPE(-134.254,-134.254,58.916,58.916) Mount Logan ENVELOPE(-140.405,-140.405,60.567,60.567) Pacific |
institution |
Open Polar |
collection |
The University of Maine: DigitalCommons@UMaine |
op_collection_id |
ftmaineuniv |
language |
unknown |
topic |
surface snow coastal northeast pacific paleoclimate interpretations δ18O Earth Sciences Environmental Sciences |
spellingShingle |
surface snow coastal northeast pacific paleoclimate interpretations δ18O Earth Sciences Environmental Sciences Koehler, Matthew C. Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations |
topic_facet |
surface snow coastal northeast pacific paleoclimate interpretations δ18O Earth Sciences Environmental Sciences |
description |
Stable water isotope ratios (18O and D) in snow pit (Juneau Icefield) and fresh snow (Eclipse Icefield) samples are included in a compilation of all available snow isotope data from coastal Alaska, and used to evaluate observed isotope shifts in regional paleoclimate records. I compiled existing isotope data in coastal Alaska (primarily the Saint Elias Range) in order to better understand the elevation dependence of stable atmospheric water isotope ratios in the region. The values that make up the compilation are reflective of multiple fractionation regimes associated with synoptic scale cyclonic events, described using the Cyclone-Water Isotope Model (Holdsworth and Krouse 2002). Using this Cyclone-Water Isotope Model as a link between high frequency spatial and temporal variability, fresh snow data characterizing five different events within a 17 day time span from the Eclipse Icefield were analyzed for δ18O values. Average isotope values among these five events vary by as much as 8‰. Meteorological conditions over the domain are investigated with NCEP Climate Forecast System Reanalysis (CFSR), and show that events with more depleted δ18O are associated with systems that have higher pressure and a zonal (northern) moisture source, whereas events with less depleted δ18O are related to events with lower pressure and a more significant component of southern moisture. These observations of event-based meteorological controls on δ18O variability shed light on paleoclimate interpretations of shifts in the isotopic record seen in the Mount Logan ice core and Jellybean Lake sediment core at around A.D. 800 and A.D. 1840. The findings in the paper support Fields et al. (2010) in the interpretation that the shift to lower δ18O values seen in the isotopic record is caused by a transition to a more zonal (northern) moisture source paradigm. |
format |
Text |
author |
Koehler, Matthew C. |
author_facet |
Koehler, Matthew C. |
author_sort |
Koehler, Matthew C. |
title |
Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations |
title_short |
Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations |
title_full |
Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations |
title_fullStr |
Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations |
title_full_unstemmed |
Investigating the Controls on Surface Snow δ18O Values in the Coastal Northeast Pacific: Implications for Paleoclimate Interpretations |
title_sort |
investigating the controls on surface snow δ18o values in the coastal northeast pacific: implications for paleoclimate interpretations |
publisher |
DigitalCommons@UMaine |
publishDate |
2013 |
url |
https://digitalcommons.library.umaine.edu/honors/125 https://digitalcommons.library.umaine.edu/context/honors/article/1123/viewcontent/Koehler_Thesis.pdf |
long_lat |
ENVELOPE(166.583,166.583,-72.133,-72.133) ENVELOPE(-134.254,-134.254,58.916,58.916) ENVELOPE(-140.405,-140.405,60.567,60.567) |
geographic |
Holdsworth Juneau Icefield Mount Logan Pacific |
geographic_facet |
Holdsworth Juneau Icefield Mount Logan Pacific |
genre |
ice core Alaska |
genre_facet |
ice core Alaska |
op_source |
Honors College |
op_relation |
https://digitalcommons.library.umaine.edu/honors/125 https://digitalcommons.library.umaine.edu/context/honors/article/1123/viewcontent/Koehler_Thesis.pdf |
_version_ |
1768388754539544576 |