NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades
Greenland ice cores provide information about past climate. However, the number of firn and ice cores from Greenland are limited and thus the spatial variability of the chemical impurities used as proxies is largely unconstrained. Furthermore, few impurity records covering the past two decades exist...
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ftcopernicus:oai:publications.copernicus.org:cpd96573 2023-05-15T15:39:10+02:00 NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades Kjær, Helle Astrid Zens, Patrick Black, Samuel Lund, Kasper Holst Svensson, Anders Vallelonga, Paul 2021-08-16 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/cp-2021-99 https://cp.copernicus.org/preprints/cp-2021-99/ eng eng info:eu-repo/grantAgreement/EC/FP7/610055 doi:10.5194/cp-2021-99 https://cp.copernicus.org/preprints/cp-2021-99/ info:eu-repo/semantics/openAccess eISSN: 1814-9332 info:eu-repo/semantics/Text 2021 ftcopernicus https://doi.org/10.5194/cp-2021-99 2021-08-23T16:22:29Z Greenland ice cores provide information about past climate. However, the number of firn and ice cores from Greenland are limited and thus the spatial variability of the chemical impurities used as proxies is largely unconstrained. Furthermore, few impurity records covering the past two decades exist from Greenland. We have by means of Continuous Flow analysis investigated 6 shallow firn cores obtained in Northern Greenland as part of the NEEM to EastGRIP traverse in 2015. The oldest reach back to 1966. The annual mean and quartiles of the insoluble dust, ammonium, and calcium concentrations in the 6 firn cores spanning a distance of 426 km overlap, and also the seasonal cycles have similar peaks in timing and magnitude across sites. Peroxide (H 2 O 2 ) is accumulation dependent and varies from site to site and conductivity, likely influenced by sea salts, also vary spatially. The temporal variability of the records is further assessed. We find no evidence for increases in total dust concentration, but find an increase in the large dust particle fluxes that we contribute to an activation of Greenland local sources in the recent years (1998–2015). We observe the expected acid and conductivity increase in the mid 70’s as a result of anthropogenic contamination and the following decrease due to mitigation. After detrending using the five year average the conductivity and acid records several volcanic horizons were identified and associated with Icelandic eruptions and volcanic eruptions in the Barents sea region. By creating a composite based on excess ammonium compared to the five year running average, we obtain a robust forest fire proxy associated primarily with Canadian forest fires (R = 0.51). We also note that the peak ammonium in the individual firn cores appear more scattered between cores than the peak volcanic layers, suggesting that the forest fire signal is more dispersed in the atmosphere than the acid from volcanic eruptions. Other/Unknown Material Barents Sea Greenland Greenland ice cores ice core Copernicus Publications: E-Journals Barents Sea Greenland |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Greenland ice cores provide information about past climate. However, the number of firn and ice cores from Greenland are limited and thus the spatial variability of the chemical impurities used as proxies is largely unconstrained. Furthermore, few impurity records covering the past two decades exist from Greenland. We have by means of Continuous Flow analysis investigated 6 shallow firn cores obtained in Northern Greenland as part of the NEEM to EastGRIP traverse in 2015. The oldest reach back to 1966. The annual mean and quartiles of the insoluble dust, ammonium, and calcium concentrations in the 6 firn cores spanning a distance of 426 km overlap, and also the seasonal cycles have similar peaks in timing and magnitude across sites. Peroxide (H 2 O 2 ) is accumulation dependent and varies from site to site and conductivity, likely influenced by sea salts, also vary spatially. The temporal variability of the records is further assessed. We find no evidence for increases in total dust concentration, but find an increase in the large dust particle fluxes that we contribute to an activation of Greenland local sources in the recent years (1998–2015). We observe the expected acid and conductivity increase in the mid 70’s as a result of anthropogenic contamination and the following decrease due to mitigation. After detrending using the five year average the conductivity and acid records several volcanic horizons were identified and associated with Icelandic eruptions and volcanic eruptions in the Barents sea region. By creating a composite based on excess ammonium compared to the five year running average, we obtain a robust forest fire proxy associated primarily with Canadian forest fires (R = 0.51). We also note that the peak ammonium in the individual firn cores appear more scattered between cores than the peak volcanic layers, suggesting that the forest fire signal is more dispersed in the atmosphere than the acid from volcanic eruptions. |
format |
Other/Unknown Material |
author |
Kjær, Helle Astrid Zens, Patrick Black, Samuel Lund, Kasper Holst Svensson, Anders Vallelonga, Paul |
spellingShingle |
Kjær, Helle Astrid Zens, Patrick Black, Samuel Lund, Kasper Holst Svensson, Anders Vallelonga, Paul NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
author_facet |
Kjær, Helle Astrid Zens, Patrick Black, Samuel Lund, Kasper Holst Svensson, Anders Vallelonga, Paul |
author_sort |
Kjær, Helle Astrid |
title |
NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
title_short |
NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
title_full |
NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
title_fullStr |
NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
title_full_unstemmed |
NEEM to EastGRIP Traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
title_sort |
neem to eastgrip traverse – spatial variability, seasonality, extreme events and trends in common ice core proxies over the past decades |
publishDate |
2021 |
url |
https://doi.org/10.5194/cp-2021-99 https://cp.copernicus.org/preprints/cp-2021-99/ |
geographic |
Barents Sea Greenland |
geographic_facet |
Barents Sea Greenland |
genre |
Barents Sea Greenland Greenland ice cores ice core |
genre_facet |
Barents Sea Greenland Greenland ice cores ice core |
op_source |
eISSN: 1814-9332 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/610055 doi:10.5194/cp-2021-99 https://cp.copernicus.org/preprints/cp-2021-99/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/cp-2021-99 |
_version_ |
1766370639189377024 |