Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles
The isotopic composition of water in ice sheets is extensively used to infer past climate changes. In low-accumulation regions their interpretation is, however, challenged by poorly constrained effects that may influence the initial isotope signal during and after deposition of the snow. This is ref...
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ftdatacite:10.25932/publishup-41876 2023-05-15T13:39:54+02:00 Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles Münch, Thomas Kipfstuhl, Sepp Freitag, Johannes Meyer, Hanno Laepple, Thomas 2019 application/pdf application/zip https://dx.doi.org/10.25932/publishup-41876 https://publishup.uni-potsdam.de/41876 en eng Universität Potsdam Creative Commons - Namensnennung, 4.0 International https://creativecommons.org/licenses/by/4.0 CC-BY article-journal Text ScholarlyArticle 2019 ftdatacite https://doi.org/10.25932/publishup-41876 2021-11-05T12:55:41Z The isotopic composition of water in ice sheets is extensively used to infer past climate changes. In low-accumulation regions their interpretation is, however, challenged by poorly constrained effects that may influence the initial isotope signal during and after deposition of the snow. This is reflected in snow-pit isotope data from Kohnen Station, Antarctica, which exhibit a seasonal cycle but also strong interannual variations that contradict local temperature observations. These inconsistencies persist even after averaging many profiles and are thus not explained by local stratigraphic noise. Previous studies have suggested that post-depositional processes may significantly influence the isotopic composition of East Antarctic firn. Here, we investigate the importance of post-depositional processes within the open-porous firn (greater than or similar to 10 cm depth) at Kohnen Station by separating spatial from temporal variability. To this end, we analyse 22 isotope profiles obtained from two snow trenches and examine the temporal isotope modifications by comparing the new data with published trench data extracted 2 years earlier. The initial isotope profiles undergo changes over time due to downward advection, firn diffusion and densification in magnitudes consistent with independent estimates. Beyond that, we find further modifications of the original isotope record to be unlikely or small in magnitude (<< 1 parts per thousand RMSD). These results show that the discrepancy between local temperatures and isotopes most likely originates from spatially coherent processes prior to or during deposition, such as precipitation intermittency or systematic isotope modifications acting on drifting or loose surface snow. : Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 662 Text Antarc* Antarctic Antarctica DataCite Metadata Store (German National Library of Science and Technology) Antarctic Kohnen ENVELOPE(0.000,0.000,-75.000,-75.000) Kohnen Station ENVELOPE(0.000,0.000,-75.000,-75.000) |
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Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
description |
The isotopic composition of water in ice sheets is extensively used to infer past climate changes. In low-accumulation regions their interpretation is, however, challenged by poorly constrained effects that may influence the initial isotope signal during and after deposition of the snow. This is reflected in snow-pit isotope data from Kohnen Station, Antarctica, which exhibit a seasonal cycle but also strong interannual variations that contradict local temperature observations. These inconsistencies persist even after averaging many profiles and are thus not explained by local stratigraphic noise. Previous studies have suggested that post-depositional processes may significantly influence the isotopic composition of East Antarctic firn. Here, we investigate the importance of post-depositional processes within the open-porous firn (greater than or similar to 10 cm depth) at Kohnen Station by separating spatial from temporal variability. To this end, we analyse 22 isotope profiles obtained from two snow trenches and examine the temporal isotope modifications by comparing the new data with published trench data extracted 2 years earlier. The initial isotope profiles undergo changes over time due to downward advection, firn diffusion and densification in magnitudes consistent with independent estimates. Beyond that, we find further modifications of the original isotope record to be unlikely or small in magnitude (<< 1 parts per thousand RMSD). These results show that the discrepancy between local temperatures and isotopes most likely originates from spatially coherent processes prior to or during deposition, such as precipitation intermittency or systematic isotope modifications acting on drifting or loose surface snow. : Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 662 |
format |
Text |
author |
Münch, Thomas Kipfstuhl, Sepp Freitag, Johannes Meyer, Hanno Laepple, Thomas |
spellingShingle |
Münch, Thomas Kipfstuhl, Sepp Freitag, Johannes Meyer, Hanno Laepple, Thomas Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles |
author_facet |
Münch, Thomas Kipfstuhl, Sepp Freitag, Johannes Meyer, Hanno Laepple, Thomas |
author_sort |
Münch, Thomas |
title |
Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles |
title_short |
Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles |
title_full |
Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles |
title_fullStr |
Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles |
title_full_unstemmed |
Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles |
title_sort |
constraints on post-depositional isotope modifications in east antarctic firn from analysing temporal changes of isotope profiles |
publisher |
Universität Potsdam |
publishDate |
2019 |
url |
https://dx.doi.org/10.25932/publishup-41876 https://publishup.uni-potsdam.de/41876 |
long_lat |
ENVELOPE(0.000,0.000,-75.000,-75.000) ENVELOPE(0.000,0.000,-75.000,-75.000) |
geographic |
Antarctic Kohnen Kohnen Station |
geographic_facet |
Antarctic Kohnen Kohnen Station |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_rights |
Creative Commons - Namensnennung, 4.0 International https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.25932/publishup-41876 |
_version_ |
1766125956015063040 |