The influence of impurities on the densification of firn -a case study from North Greenland
Paleoclimatic records from polar ice cores provide unique information about past atmospheric conditions, like temperature from stable water isotopes and greenhouse gas concentrations. To investigate leads and lags of temperature, measured in the ice phase, with gas concentration the exact dating of...
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ftawi:oai:epic.awi.de:25678 2024-09-09T19:43:19+00:00 The influence of impurities on the densification of firn -a case study from North Greenland Weißbach, Stefanie Wegner, Anna Freitag, Johannes Kipfstuhl, Sepp 2012 application/pdf https://epic.awi.de/id/eprint/25678/ https://epic.awi.de/id/eprint/25678/1/epic-egu.pdf https://hdl.handle.net/10013/epic.39264 https://hdl.handle.net/10013/epic.39264.d001 unknown https://epic.awi.de/id/eprint/25678/1/epic-egu.pdf https://hdl.handle.net/10013/epic.39264.d001 Weißbach, S. , Wegner, A. , Freitag, J. orcid:0000-0003-2654-9440 and Kipfstuhl, S. (2012) The influence of impurities on the densification of firn -a case study from North Greenland , Geophysical Research Abstracts Vol. 14, EGU2012-10143, EGU General Assembly, Vienna, 22 April 2012 - 27 April 2012 . hdl:10013/epic.39264 EPIC3Geophysical Research Abstracts Vol. 14, EGU2012-10143, EGU General Assembly, Vienna, 2012-04-22-2012-04-27 Conference notRev 2012 ftawi 2024-06-24T04:03:41Z Paleoclimatic records from polar ice cores provide unique information about past atmospheric conditions, like temperature from stable water isotopes and greenhouse gas concentrations. To investigate leads and lags of temperature, measured in the ice phase, with gas concentration the exact dating of gas and ice is important. However, the age difference between the air and the surrounding ice complicates the exact dating. After the deposition the age of the snow increases with depth, whereas the pores only close in a certain depth, so called close-off depth (COD). Thus, the knowledge of the COD is crucial for dating the gas. Snow accumulation rate and temperature are known as the main factors of firn densification. Recently, a possible influence of impurities enclosed in the ice was found. Here, we present a case study to investigate which impurities could have an influence on the densification of polar firn. We have analyzed 80 cm from an unbroken firn core from north-west Greenland from a depth of ~54 m, next to the firn-ice transition. Here the density is of very high variability. We can differentiate between layers of different densities in spite of the same temperatures and snow accumulation rates and its deep enough to analyse the influence of trace elements. We measured the density using a new full core X-ray computer tomograph with a resolution of 113 µm. We analysed major ions (SO42-, CH3SO3-, NH4+, NO3-, F-, Br-, Na+, Cl-, K+, Ca2+ and Mg2+) and dust particles on discrete samples in 3-4 mm resolution and compared the obtained concentration profiles with the density of the firn. The uncertainty in depth correspondence is less than 1 mm, thus a comparison on this level is possible for the first time. We found the highest correlations between the dust proxies (particle concentration and Ca2+-concentration), r = 0.6, indicating an influence of these impurities on the densification of firn. Correlation coefficients between other ion concentrations and the density range from r = -0.04 (F-) to r = 0.27 (NO3-). ... Conference Object Greenland North Greenland Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Greenland |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Paleoclimatic records from polar ice cores provide unique information about past atmospheric conditions, like temperature from stable water isotopes and greenhouse gas concentrations. To investigate leads and lags of temperature, measured in the ice phase, with gas concentration the exact dating of gas and ice is important. However, the age difference between the air and the surrounding ice complicates the exact dating. After the deposition the age of the snow increases with depth, whereas the pores only close in a certain depth, so called close-off depth (COD). Thus, the knowledge of the COD is crucial for dating the gas. Snow accumulation rate and temperature are known as the main factors of firn densification. Recently, a possible influence of impurities enclosed in the ice was found. Here, we present a case study to investigate which impurities could have an influence on the densification of polar firn. We have analyzed 80 cm from an unbroken firn core from north-west Greenland from a depth of ~54 m, next to the firn-ice transition. Here the density is of very high variability. We can differentiate between layers of different densities in spite of the same temperatures and snow accumulation rates and its deep enough to analyse the influence of trace elements. We measured the density using a new full core X-ray computer tomograph with a resolution of 113 µm. We analysed major ions (SO42-, CH3SO3-, NH4+, NO3-, F-, Br-, Na+, Cl-, K+, Ca2+ and Mg2+) and dust particles on discrete samples in 3-4 mm resolution and compared the obtained concentration profiles with the density of the firn. The uncertainty in depth correspondence is less than 1 mm, thus a comparison on this level is possible for the first time. We found the highest correlations between the dust proxies (particle concentration and Ca2+-concentration), r = 0.6, indicating an influence of these impurities on the densification of firn. Correlation coefficients between other ion concentrations and the density range from r = -0.04 (F-) to r = 0.27 (NO3-). ... |
format |
Conference Object |
author |
Weißbach, Stefanie Wegner, Anna Freitag, Johannes Kipfstuhl, Sepp |
spellingShingle |
Weißbach, Stefanie Wegner, Anna Freitag, Johannes Kipfstuhl, Sepp The influence of impurities on the densification of firn -a case study from North Greenland |
author_facet |
Weißbach, Stefanie Wegner, Anna Freitag, Johannes Kipfstuhl, Sepp |
author_sort |
Weißbach, Stefanie |
title |
The influence of impurities on the densification of firn -a case study from North Greenland |
title_short |
The influence of impurities on the densification of firn -a case study from North Greenland |
title_full |
The influence of impurities on the densification of firn -a case study from North Greenland |
title_fullStr |
The influence of impurities on the densification of firn -a case study from North Greenland |
title_full_unstemmed |
The influence of impurities on the densification of firn -a case study from North Greenland |
title_sort |
influence of impurities on the densification of firn -a case study from north greenland |
publishDate |
2012 |
url |
https://epic.awi.de/id/eprint/25678/ https://epic.awi.de/id/eprint/25678/1/epic-egu.pdf https://hdl.handle.net/10013/epic.39264 https://hdl.handle.net/10013/epic.39264.d001 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland North Greenland |
genre_facet |
Greenland North Greenland |
op_source |
EPIC3Geophysical Research Abstracts Vol. 14, EGU2012-10143, EGU General Assembly, Vienna, 2012-04-22-2012-04-27 |
op_relation |
https://epic.awi.de/id/eprint/25678/1/epic-egu.pdf https://hdl.handle.net/10013/epic.39264.d001 Weißbach, S. , Wegner, A. , Freitag, J. orcid:0000-0003-2654-9440 and Kipfstuhl, S. (2012) The influence of impurities on the densification of firn -a case study from North Greenland , Geophysical Research Abstracts Vol. 14, EGU2012-10143, EGU General Assembly, Vienna, 22 April 2012 - 27 April 2012 . hdl:10013/epic.39264 |
_version_ |
1809912655860727808 |