Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications
Cryoconite is a mixture of impurities and ice visually represented by dark colors present in the ablation zone of glaciers. As an important constituent of light-absorbing impurities on the glacier surface, iron oxides influence the radiative properties of mineral dust and thus its impact on ice melt...
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Copernicus Publications
2018
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00004426 2023-05-15T18:32:32+02:00 Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications Cong, Zhiyuan Gao, Shaopeng Zhao, Wancang Wang, Xin Wu, Guangming Zhang, Yulan Kang, Shichang Liu, Yongqin Ji, Junfeng 2018-10 electronic https://doi.org/10.5194/tc-12-3177-2018 https://noa.gwlb.de/receive/cop_mods_00004426 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00004383/tc-12-3177-2018.pdf https://tc.copernicus.org/articles/12/3177/2018/tc-12-3177-2018.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-12-3177-2018 https://noa.gwlb.de/receive/cop_mods_00004426 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00004383/tc-12-3177-2018.pdf https://tc.copernicus.org/articles/12/3177/2018/tc-12-3177-2018.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2018 ftnonlinearchiv https://doi.org/10.5194/tc-12-3177-2018 2022-02-08T23:00:06Z Cryoconite is a mixture of impurities and ice visually represented by dark colors present in the ablation zone of glaciers. As an important constituent of light-absorbing impurities on the glacier surface, iron oxides influence the radiative properties of mineral dust and thus its impact on ice melting processes. In particular, the distinct optical properties between hematite and goethite (the major iron oxide species) highlight the necessity to obtain accurate knowledge about their abundance and geochemical behavior. Cryoconite samples from five glaciers in different regions of the Tibetan Plateau (TP) and surroundings were studied. The iron abundance in the cryoconite from TP glaciers ranged from 3.40 % to 4.90 % by mass, in accordance with typical natural background levels. Because the light absorption capacity of mineral dust essentially depends on the presence of iron oxides (i.e., free iron), iron oxides were extracted and determined using diffuse reflectance spectroscopy. The ratios of free to total iron for the five glaciers ranged from 0.31 to 0.70, emphasizing that iron in the form of oxides should be considered rather than total iron in the albedo and radiative modeling. Furthermore, the goethite content in iron oxides (in mass fraction) ranged from 81 % to 98 %, showing that goethite was the predominant form among the glaciers. Using the abundance and speciation of iron oxides as well as their optical properties, the total light absorption was quantitatively attributed to goethite, hematite, black carbon (BC) and organic matters at 450 and 600 nm wavelengths. We found that the goethite played a stronger role than BC at shorter wavelengths for most glaciers. Such findings were essential to understand the relative significance of anthropogenic and natural effects, and then taking the proper mitigation measures. Article in Journal/Newspaper The Cryosphere Niedersächsisches Online-Archiv NOA The Cryosphere 12 10 3177 3186 |
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article Verlagsveröffentlichung Cong, Zhiyuan Gao, Shaopeng Zhao, Wancang Wang, Xin Wu, Guangming Zhang, Yulan Kang, Shichang Liu, Yongqin Ji, Junfeng Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications |
topic_facet |
article Verlagsveröffentlichung |
description |
Cryoconite is a mixture of impurities and ice visually represented by dark colors present in the ablation zone of glaciers. As an important constituent of light-absorbing impurities on the glacier surface, iron oxides influence the radiative properties of mineral dust and thus its impact on ice melting processes. In particular, the distinct optical properties between hematite and goethite (the major iron oxide species) highlight the necessity to obtain accurate knowledge about their abundance and geochemical behavior. Cryoconite samples from five glaciers in different regions of the Tibetan Plateau (TP) and surroundings were studied. The iron abundance in the cryoconite from TP glaciers ranged from 3.40 % to 4.90 % by mass, in accordance with typical natural background levels. Because the light absorption capacity of mineral dust essentially depends on the presence of iron oxides (i.e., free iron), iron oxides were extracted and determined using diffuse reflectance spectroscopy. The ratios of free to total iron for the five glaciers ranged from 0.31 to 0.70, emphasizing that iron in the form of oxides should be considered rather than total iron in the albedo and radiative modeling. Furthermore, the goethite content in iron oxides (in mass fraction) ranged from 81 % to 98 %, showing that goethite was the predominant form among the glaciers. Using the abundance and speciation of iron oxides as well as their optical properties, the total light absorption was quantitatively attributed to goethite, hematite, black carbon (BC) and organic matters at 450 and 600 nm wavelengths. We found that the goethite played a stronger role than BC at shorter wavelengths for most glaciers. Such findings were essential to understand the relative significance of anthropogenic and natural effects, and then taking the proper mitigation measures. |
format |
Article in Journal/Newspaper |
author |
Cong, Zhiyuan Gao, Shaopeng Zhao, Wancang Wang, Xin Wu, Guangming Zhang, Yulan Kang, Shichang Liu, Yongqin Ji, Junfeng |
author_facet |
Cong, Zhiyuan Gao, Shaopeng Zhao, Wancang Wang, Xin Wu, Guangming Zhang, Yulan Kang, Shichang Liu, Yongqin Ji, Junfeng |
author_sort |
Cong, Zhiyuan |
title |
Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications |
title_short |
Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications |
title_full |
Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications |
title_fullStr |
Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications |
title_full_unstemmed |
Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications |
title_sort |
iron oxides in the cryoconite of glaciers on the tibetan plateau: abundance, speciation and implications |
publisher |
Copernicus Publications |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-12-3177-2018 https://noa.gwlb.de/receive/cop_mods_00004426 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00004383/tc-12-3177-2018.pdf https://tc.copernicus.org/articles/12/3177/2018/tc-12-3177-2018.pdf |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-12-3177-2018 https://noa.gwlb.de/receive/cop_mods_00004426 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00004383/tc-12-3177-2018.pdf https://tc.copernicus.org/articles/12/3177/2018/tc-12-3177-2018.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-12-3177-2018 |
container_title |
The Cryosphere |
container_volume |
12 |
container_issue |
10 |
container_start_page |
3177 |
op_container_end_page |
3186 |
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1766216661524807680 |