12 results on '"Zhang, Yulan"'
Search Results
2. Black Carbon Size in Snow of Chinese Altai Mountain in Central Asia
- Author
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Zhang, Yulan, Kang, Shichang, Gao, Tanguang, Sprenger, Michael, Zhang, Wei, and Wang, Zhaoqing
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- 2023
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3. Characteristics of carbonaceous aerosols analyzed using a multiwavelength thermal/optical carbon analyzer: A case study in Lanzhou City
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Zhang, Yulan and Kang, Shichang
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- 2019
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4. Black carbon and mineral dust on two glaciers on the central Tibetan Plateau: sources and implications.
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Li, Xiaofei, Kang, Shichang, Sprenger, Michael, Zhang, Yulan, He, Xiaobo, Zhang, Guoshuai, Tripathee, Lekhendra, Li, Chaoliu, and Cao, Junji
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CARBON-black ,MINERAL dusts ,DUST ,GLACIERS ,RADIATIVE forcing ,GLACIAL melting ,PLATEAUS - Abstract
Sources and implications of black carbon (BC) and mineral dust (MD) on two glaciers on the central Tibetan Plateau were estimated based on in situ measurements and modeling. The results indicated that BC and MD accounted for ~11 ± 1% and 4 ± 0% of the albedo reduction relative to clean snow, while the radiative forcing varied between 11 and 196 and 1–89 W m
−2 , respectively. Assessment of BC and MD contributions to the glacier melt can reach up 88 to 434 and 35 to 187 mm w.e., respectively, contributing ~9–23 and 4–10% of the total glacier melt. A footprint analysis indicated that BC and MD deposited on the glaciers originated mainly from the Middle East, Central Asia, North China and South Asia during the study period. Moreover, a potentially large fraction of BC may have originated from local and regional fossil fuel combustion. This study suggests that BC and MD will enhance glacier melt and provides a scientific basis for regional mitigation efforts. [ABSTRACT FROM AUTHOR]- Published
- 2020
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5. Dissolved organic carbon in snow cover of the Chinese Altai Mountains, Central Asia: Concentrations, sources and light-absorption properties.
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Zhang, Yulan, Kang, Shichang, Gao, Tanguang, Schmale, Julia, Liu, Yajun, Zhang, Wei, Guo, Junming, Du, Wentao, Hu, Zhaofu, Cui, Xiaoqing, and Sillanpää, Mika
- Abstract
Abstract Dissolved organic carbon (DOC) in snow plays an important role in river ecosystems that are fed by snowmelt water. However, limited knowledge is available on the DOC content in snow of the Chinese Altai Mountains in Central Asia. In this study, DOC in the snow cover of the Kayiertesi river basin, southern slope of Altai Mountains, was investigated during November 2016 to April 2017. The results showed that average concentrations of DOC in the surface snow cover (1.01 ± 0.52 mg L−1) were only a little higher than those in glaciers of the Tibetan Plateau, European Alps, and Alaska, but much higher than in Greenland Ice Sheet. Depth variations of DOC concentrations from snowpack profiles indicated higher values in the surface layer. During the observation period, scavenging efficiency for DOC in snow cover is estimated to be 0.15 ± 0.10, suggesting that DOC in snow can be affected more by the meltwater during ablation season than during accumulation season. The average mass absorption cross section at 365 nm and the absorption Ångström exponent of DOC were 0.45 ± 0.35 m2 g−1 and 2.59 ± 1.03, respectively, with higher values in March and April 2017. Fraction of radiative forcing caused by DOC relative to black carbon accounted for about 10.5%, implying DOC is a non-ignorable light-absorber of solar radiation in snow of the Altai regions. Backward trajectories analysis and aerosol vertical distribution images from satellites showed that DOC in the snow of the Altai Mountains was mainly influenced by air masses from Central Asia, Western Siberia, the Middle East, and some even from Europe. Biomass burning and organic carbon mixed with mineral dust contributed significantly to the DOC concentration. This study highlights the effects of DOC in the snow cover for radiative forcing and the need to study carbon cycling for evaluation of quality of the downstreams ecosystems. Graphical abstract Unlabelled Image Highlights • Characteristics of DOC were analyzed in snow cover of Chinese Altai Mountains. • DOC in the surface snow cover was little higher than those in glaciers of the Tibetan Plateau, European Alps, and Alaska. • The average MAC 365 nm and AAE 330−400 nm of DOC were 0.45 ± 0.35 m2 g−1 and 2.59 ± 1.03, respectively. • Fraction of radiative forcing caused by DOC relative to BC accounted for about 10.5%. • DOC is mainly influenced by air masses from Central Asia, Western Siberia, the Middle East, and some even from Europe. [ABSTRACT FROM AUTHOR]
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- 2019
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6. Characteristics of black carbon in snow from Laohugou No. 12 glacier on the northern Tibetan Plateau.
- Author
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Zhang, Yulan, Kang, Shichang, Li, Chaoliu, Gao, Tanguang, Cong, Zhiyuan, Sprenger, Michael, Liu, Yajun, Li, Xiaofei, Guo, Junming, Sillanpää, Mika, Wang, Kun, Chen, Jizu, Li, Yang, and Sun, Shiwei
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RAINFALL , *BLIZZARDS , *SOOT , *SCANNING transmission electron microscopy , *SCANNING electron microscopy - Abstract
Black carbon (BC) emitted from the incomplete combustion of biomass and fossil fuel impacts the climate system, cryospheric change, and human health. This study documents black carbon deposition in snow from a benchmark glacier on the northern Tibetan Plateau. Significant seasonality of BC concentrations indicates different input or post-depositional processes. BC particles deposited in snow had a mass volume median diameter slightly larger than that of black carbon particles typically found in the atmosphere. Also, unlike black carbon particles in the atmosphere, the particles deposited in snow did not exhibit highly fractal morphology by Scanning Transmission Electron Microscope. Footprint analysis indicated BC deposited on the glacier in summer originated mainly from Central Asia; in winter, the depositing air masses generally originated from Central Asia and Pakistan. Anthropogenic emissions play an important role on black carbon deposition in glacial snow, especially in winter. The mass absorption efficiency of BC in snow at 632 nm exhibited significantly seasonality, with higher values in summer and lower values in winter. The information on black carbon deposition in glacial snow provided in this study could be used to help mitigate the impacts of BC on glacier melting on the northern Tibetan Plateau. [ABSTRACT FROM AUTHOR]
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- 2017
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7. A review of black carbon in snow and ice and its impact on the cryosphere.
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Kang, Shichang, Zhang, Yulan, Qian, Yun, and Wang, Hailong
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CRYOSPHERE , *CARBON-black , *SNOW , *SOOT , *SNOW cover , *ALPINE glaciers , *ABLATION (Glaciology) , *GLACIERS - Abstract
Black carbon (BC) has emerged as an important short-lived climate forcer. Due to its light absorption properties, BC can darken the snow/ice surface, affect the energy balance, and further lead to acceleration of the melting of the cryosphere (e.g., glaciers, snow cover, and sea ice). By reviewing the recent published literatures, we present an overview of the historical changes, spatial distribution of BC in snow/ice, and how these changes are related to the cryospheric melting. Ice core records show a rapid increase of BC concentrations that began in the 1850s and continued throughout the 20th century, which is consistent with an increase of BC emissions owing to industrialization. A decrease of BC amount since 1970s in Arctic and European ice cores has been partially attributed to the Clean Air Act. However, in the Himalayas, BC records show a continuous increase during this period. Generally, BC concentrations in snow and ice in the mid-latitude regions are one to two orders of magnitude higher than those in the polar regions. In particular, BC concentrations in aged snow and granular ice in the ablation areas of mountain glaciers are one to three orders of magnitude higher than those in fresh snow or snowpits in the glacier accumulation areas due to BC accumulation during melting season. BC in the surface snow/ice is responsible for about 20% of the albedo reduction in the Tibetan Plateau during glacier melt season. Globally, observations and modeling results indicate that radiative forcing (RF) induced by BC in snow and ice is highest in the mid-latitudes, ranging from several W m−2 in fresh snow to hundreds of W m−2 in aged snow and granular ice in the glacier ablation areas. The large BC-in-snow RF and associated snow albedo feedback lead to an acceleration in the total glacier melt (approximately 20%) and/or a reduction in the duration of the snow cover by several days, resulting in an increase of glacier discharge. Given our limited understanding of quantifying the role of BC in cryospheric melting, it is important to synthesize the existing research on the multi-scale processes related to BC in snow and ice to identify the gaps in our understanding of these processes and to propose a path forward to improve the quality of our observations of the aforementioned phenomena to fill these gaps. [ABSTRACT FROM AUTHOR]
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- 2020
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8. Effects of black carbon and mineral dust on glacial melting on the Muz Taw glacier, Central Asia.
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Zhang, Yulan, Gao, Tanguang, Kang, Shichang, Sprenger, Michael, Tao, Shu, Du, Wentao, Yang, Junhua, Wang, Feiteng, and Meng, Wenjun
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Light-absorbing impurities (LAIs), including black carbon (BC) and mineral dust, in snow can trigger a positive feedback. In this study, we estimate the contribution of BC and dust to glacial melting in Central Asia. Average BC and dust concentrations in the surface snow of the Muz Taw glacier are 1788 ± 1754 ng g−1 and 172 ± 178 μg g−1, respectively. Simulation using the Snow Ice and Aerosol Radiation (SNICAR) model indicates that the combined effect of BC and dust reduces the snow albedo by approximately 6.24% to 50.4% relative to clean snow. Radiative forcing (RF) induced by BC and dust deposited in snow ranges from 1.61 to 32.69 W m−2, with an average of 16.74 W m−2 for the central scenario. Thus, glacier melting can be enhanced by 36.37 cm w.e. by BC and dust in snow, accounting for about 16.3% of the total glacier melt. LAIs deposited on the Muz Taw glacier mostly originate from Central Asia, West Siberia and local emissions during the study period. More than 80% of BC deposited is attributed to anthropogenic emissions. These results strengthen the important role of BC and dust in glacier melting in Central Asia, and further highlights the potential benefits of mitigation of BC emissions. Unlabelled Image • LAIs in snow of a glacier in Central Asia are studied. • BC plays a bigger role than dust in the albedo reduction and radiative forcing. • Glacier melting due to BC and dust in snow accounts for ~16% of the total melt. • LAIs deposited on the Muz Taw glacier mainly originate from Central Asia and western Siberia. • More than 80% of BC deposited on the glacier is attributed to anthropogenic emissions. [ABSTRACT FROM AUTHOR]
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- 2020
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9. Distribution of light-absorbing impurities in snow of glacier on Mt. Yulong, southeastern Tibetan Plateau.
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Niu, Hewen, Kang, Shichang, Zhang, Yulan, Shi, Xiaoyi, Shi, Xiaofei, Wang, Shijin, Li, Gang, Yan, Xingguo, Pu, Tao, and He, Yuanqing
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LIGHT absorption , *SNOWMELT , *GLACIERS , *INDUSTRIAL contamination , *RADIATIVE forcing - Abstract
Insoluble light-absorbing impurities (ILAIs) in surface snow of glacier reduce snow albedo and accelerate glacier melt. In order to assess effects of ILAIs on glacier melt, we present the first results from field measurements of ILAIs, including black carbon (BC) and dust in snowpacks of glacier on Mt. Yulong, southeastern Tibetan Plateau (TP). Amplification factors because of snow melt were calculated for BC and dust concentrations in surface snow, and melt scavenging rates, effects of ILAIs on snow spectral albedo, and associated radiative forcing (RF) were estimated. Melt amplification generally appeared to be confined to the top few centimeters of the snowpack, and our results indicated that BC was more efficiently scavenged with meltwater than the other insoluble light-absorbers (e.g., dust). Absorbing impurities reduced snow spectral albedo more with larger particulate grain radius ( r e ). Spectral albedo reduction was investigated using the SNow ICe Aerosol Radiative (SNICAR) model. Albedo reduction for 1200 ng g − 1 of BC in Mt. Yulong snow was 0.075 for snow with r e = 500 compared with r e = 200 μm. If dust (51.37 ppm) was the only impurity in the snowpack, the spectral albedo reduction would be only 0.03, and the associated RF was 42.76 W m − 2 . For a BC and dust mixed scenario, the spectral albedo was substantially reduced (0.11 ± 0.03), and the associated RF (145.23 W m − 2 ) was more than three times larger than that for the dust-only scenario. BC in snow is an active factor controlling snow albedo and snow-ice RF. Further observational studies are needed to quantify the contribution of BC and dust to albedo reduction and glacier melt and to characterize the variation of glacier RF. [ABSTRACT FROM AUTHOR]
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- 2017
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10. Sources, characteristics and climate impact of light-absorbing aerosols over the Tibetan Plateau.
- Author
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Chen, Siyu, Zhang, Renhe, Mao, Rui, Zhang, Yulan, Chen, Yu, Ji, Zhenming, Gong, Yongqi, and Guan, Yawen
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ICE cores , *AEROSOLS , *EFFECT of human beings on climate change , *CLIMATE change , *BIOMASS burning , *HYDROLOGIC cycle - Abstract
Known as the "third pole" and "water tower of Asia", the Tibetan Plateau (TP) is the home to the largest number of glaciers in the mid-latitudes and one of the most sensitive areas to global climate change due to its special geographical location and powerful thermodynamic effects. In recent years, the TP has been affected by exogenous pollutants and the concentrations of some pollutants have shown an increasing trend, especially light-absorbing aerosols (LAAs), when ice core records, ground- and aircraft-based field campaigns and satellite technology enabled synthesized monitoring. The enhanced warming of the vast majority of regions in TP, together with Arctic warming, and snow/ice decline, represents credible evidence of anthropogenic climate change. This paper provides a comprehensive review of studies on the sources, characteristics and climate impacts of LAAs over the TP. Adjacent to the two major emission sources of LAAs in East Asia and South Asia, the unique geographical location and climatic characteristics of the TP make it possible for TP LAAs to cause atmospheric warming and accelerated glacier melting, affecting the hydrological cycle in South Asia, East Asia and even the Northern Hemisphere, thus causing a series of serious environmental and social problems. LAAs, such as black carbon and dust, can strongly absorb solar radiation and and have significantly influence on climate change. Moreover, light-absorbing impurities (LAIs) on snow/ice can reduce the snow/ice albedo and further accelerate the snow/ice melting. Both LAAs and LAIs over the TP can induce thermodynamic feedback processes, cause significant warming of the TP and then lead to a strengthening of the early monsoon and affect the subsequent evolution of the monsoon. Many mechanisms have been proposed forth regarding how TP LAAs modulate the phase, intensity, and amplitude of the Asian climate system. A wide range of theoretical, observational, and modeling findings on TP LAAs and their climate impacts are synthesized, in which dust aerosols from drylands and black carbon from biomass burning are considered leading components. By coupling an integrated approach with state-of-the-art modeling, high temporal and fine spatial resolution remote sensing observations with increasing sampling over the TP will provide further insights into TP aerosols. • Light-absorbing aerosols warm the Tibetan Plateau, further influence climate system • The external input of light-absorbing aerosols over the Tibetan Plateau is dominant • Climate effects of light-absorbing aerosols or impurities in snow is divergent [ABSTRACT FROM AUTHOR]
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- 2022
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11. Black carbon and dust in the Third Pole glaciers: Revaluated concentrations, mass absorption cross-sections and contributions to glacier ablation.
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Li, Yang, Kang, Shichang, Zhang, Xuelei, Chen, Jizu, Schmale, Julia, Li, Xiaofei, Zhang, Yulan, Niu, Hewen, Li, Zhongqin, Qin, Xiang, He, Xiaobo, Yang, Wei, Zhang, Guoshuai, Wang, Shijin, Shao, Lili, and Tian, Lide
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- 2021
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12. Black carbon and mercury in the surface sediments of Selin Co, central Tibetan Plateau: Covariation with total carbon.
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Neupane, Bigyan, Wang, Junbo, Kang, Shichang, Zhang, Yulan, Chen, Pengfei, Rai, Mukesh, Guo, Junming, Yu, Siwei, and Thapa, Poonam
- Abstract
Tibetan Plateau (TP) is an important geographical region for investigating the long-range transport of pollutants as limited emission sources exist in this region. In this study, based on analysis of 61 surface samples, we report the spatial distribution and concentrations of BC, Hg, total organic carbon (TOC) and inorganic carbon (IC) in surface sediments of Selin Co, the largest lake in central Tibet. The mean BC and Hg concentrations were 0.62 ± 0.34 mg/g and 32.03 ± 9.88 ng/g (range: 0.03–1.47 mg/g and 13.83–51.81 ng/g respectively), which were lower than the values from other lakes in the Himalayan-Tibetan Plateau (HTP). BC and Hg exhibited similar spatial distribution in the surface sediments. Similarly, the mean TOC and IC were 2.19 ± 1.46% and 3.13 ± 1.07% (range: 0.0007–7.78% and 0.30–5.30% respectively). BC/TOC ratio, as well as char/soot ratio, suggests biomass burning as a major source of BC in the sediments via the influence of long-range transport. The positive correlation between the concentrations of BC and Hg suggests similar emission sources or transport pathway. Concentrations of BC and Hg were higher in fine grain particles (size <~50 μm) which were capable of transport and deposit in the deeper part of the lake, as suggested by a significant relationship between water depth and particle size. This study elucidates the extent of pollution in very recent ages and also could serve as the basis for paleo-environmental studies in future. Figure showing the spatial distribution of BC, Hg and TC. Unlabelled Image • Average BC and Hg concentrations were lower than reported in other lakes of the HTP. • Fine grain particles exhibited higher concentration of BC and Hg. • Fine grain particles were capable of transport and deposit in deeper part of the lake. • Source interpretation suggested biomass burning as a major source of BC. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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