Provenance of cryoconite deposited on the glaciers of the Tibetan Plateau: New insights from Nd‐Sr isotopic composition and size distribution

Dong, Zhiwen; Kang, Shichang; Qin, Dahe; Li, Yang; Wang, Xuejia; Ren, Jiawen; Li, Xiaofei; Yang, Jin‐Hui; Qin, Xiang

doi:10.1002/2016jd024944

Cited by 50 publications

(59 citation statements)

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“…For example, when the particle size is 3.8 μm, the dry deposition velocity can be up to 3.0 cm/s, which is much higher than the constant (0.15 cm/s) used in a previous study (Fang et al, ). Moreover, the modal size of the volume‐size distribution in the Himalayas and Tibetan Plateau is 39.8–48.3 μm for local mineral dust and 11.5–13.4 μm for long‐range transport eolian dust (Dong et al, ). This evidence suggests that the dry deposition velocity in the Himalayas and Tibetan Plateau could be larger than that which has been generally anticipated.…”

Section: Resultsmentioning

confidence: 99%

Deposition of Organic and Black Carbon: Direct Measurements at Three Remote Stations in the Himalayas and Tibetan Plateau

Yan

Kang

et al. 2019

JGR Atmospheres

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Carbonaceous matter in the atmosphere has an important influence on climate change. Currently, the deposition of carbonaceous matter is one of the largest uncertainties in the climate system. This phenomenon is common in remote regions, such as the Himalayas and Tibetan Plateau. In this study, for the first time, we reported in situ measurements of wet and dry deposition rates of carbonaceous matter at three remote stations: Nam Co, Lulang, and Everest. The results showed that the annual wet deposition rates of water‐insoluble organic carbon (WIOC) and black carbon (BC) were 60.2 and 5.8 mg·m−2·year−1, 330 and 34.6 mg·m−2·year−1, and 47.0 and 2.6 mg·m−2·year−1 at the Nam Co, Lulang, and Everest stations, respectively. Seasonal variations in the wet deposition rates of WIOC and BC were controlled by precipitation amount and their atmospheric concentrations. In addition, the wet scavenging ratios of WIOC and BC at Nam Co Station were close to those observed in other remote areas. The total BC deposition at Nam Co Station (15.3 mg·m−2·year−1) was higher than that from chemical transport models, implying a dominant role of dry deposition of BC in the total deposition at this station and an urgent need to improve the aerosol deposition in models for the Himalayas and Tibetan Plateau. It was found that the deposition rates of carbonaceous matter in the Himalayas and Tibetan Plateau had large spatial variation; thus, high‐resolution models need to be applied in the future.

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Section: Resultsmentioning

confidence: 99%

Deposition of Organic and Black Carbon: Direct Measurements at Three Remote Stations in the Himalayas and Tibetan Plateau

Yan

Kang

et al. 2019

JGR Atmospheres

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“…Eolian dust deposited on mountain glaciers affects the radiative forcing of the glacier surface and accelerates snow and ice melting (Dong et al, ; Naegeli et al, ; Wu et al, ). Therefore, it is important to learn the long‐range transported (LRT) dust deposition under recent global climate and glacier changes.…”

Section: Introductionmentioning

confidence: 99%

“…However, the provenance of the eolian dust deposited on the glacier surfaces of the Tibetan Plateau eastern margins, in particular the southeastern parts, and their transport mechanism remain unclear. The Hf‐Nd‐Sr isotopic ratio is generally considered to be useful indicators for determining dust fingerprinting (Chen et al, ; Dong et al, , ; Lee et al, ; Schettler et al, ; Zhao et al, , ) and identifying the dust sources, as Hf, Nd, and Sr isotopes mainly depend on regional geology properties with obvious regional distribution in the Earth's crustal surface and less alteration during transport and deposition processes. Hf‐Nd‐Sr isotopes of mineral dust on the mountain glaciers from local dust may largely differ to those from LRT eolian dust, which in turn may play significant roles in regional circulation of materials (Jickells et al, ).…”

Section: Introductionmentioning

confidence: 99%

Hf‐Nd‐Sr Isotopic Composition as Fingerprint for Long‐Range Transported Eolian Dust Deposition in Glacier Snowpack of Eastern Tibetan Plateau

et al. 2018

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This study presents the Hf-Nd-Sr isotopic compositions of eolian dust deposited on glacier snowpacks along a longitude transect on the eastern Tibetan Plateau, in order to trace its source areas and the provenance of long-range transported (LRT) Asian dust on the eastern margin of Tibetan Plateau. Most of the glacier snowpack samples from northern locations (Qiyi and Lenglongling Glaciers) indicated similar Hf-Nd-Sr isotopic ratios with that of large central Asian deserts. However, the southern locations (Dagu, Hailuogou, and Baishui Glaciers) showed dramatic difference in the Hf-Nd-Sr isotopic ratios of snowpack dust compared with those of large Asian deserts, but were more similar to that of Tibetan Plateau surface crust. Hf-Nd isotopes indicated that the southern Tibetan Plateau locations are hardly influenced by central Asian dust, but probably influenced by southward dust transport from the Loess Plateau, in addition to the arid deserts on the Tibetan Plateau surface. Meteorological data and aerosol optical depth also demonstrated the potential differences of eolian dust transport and input between the north and south locations. Loess Plateau is even in today's climate a dust sink, but dust emission from the Loess Plateau is also possible. The influence of the Tibetan Plateau and southwest vortex of China to atmospheric circulation may have caused such eolian transport, in particular for LRT eolian dust transport to southeastern Tibetan Plateau glaicers. This study is also of importance in that the Hf-Nd isotopic fingerprinting could provide new evidences for LRT dust deposition on the Tibetan Plateau.Plain Language Summary This study is aimed to examine the spatial variation of eolian dust transport and deposition in the eastern margin of Tibetan Plateau, for which the sources and provenance of the dust deposited in high elevation glaciers have not been investigated. The dust transport route is also important for understanding regional atmospheric circulation and climate. This study is thus intended to provide a better understanding of long-range transported dust transport and dust deposition on the eastern margin of Tibetan Plateau. Hf-Nd isotopic fingerprinting is used to provide new evidence for tracing long-range transported dust in high mountain glaicers when compared with Nd-Sr isotopes. a The mode (dv) and standard deviation (σg) of the size distribution were calculated by a lognormal curve fitting procedure as described in the text. N is the number of samples per sample category. nd means no data available.

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“…1). In summer, their surfaces are commonly covered by incoherent impurities (granular sediment) with a dark color, which was termed cryoconite Dong et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications

et al. 2018

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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.

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Provenance of cryoconite deposited on the glaciers of the Tibetan Plateau: New insights from Nd‐Sr isotopic composition and size distribution

Cited by 50 publications

References 49 publications

Deposition of Organic and Black Carbon: Direct Measurements at Three Remote Stations in the Himalayas and Tibetan Plateau

Deposition of Organic and Black Carbon: Direct Measurements at Three Remote Stations in the Himalayas and Tibetan Plateau

Hf‐Nd‐Sr Isotopic Composition as Fingerprint for Long‐Range Transported Eolian Dust Deposition in Glacier Snowpack of Eastern Tibetan Plateau

Iron oxides in the cryoconite of glaciers on the Tibetan Plateau: abundance, speciation and implications

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