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Tibetan Plateau (TP) is known as the water tower of Asia, and glaciers are solid reservoirs that can regulate the amount of water. Black carbon (BC), as one of the important factors accelerating glacier melting, is causing evident environmental effects in snow and ice. However, a systematical summary of the potential sources, analytical methods, distributions, and environmental effects of BC in snow and ice on the TP's glaciers is scarce. Therefore, this study drew upon existing research on snow and ice BC on glaciers of the TP to describe the detection methods and uncertainties associated with them to clarify the concentrations of BC in snow and ice and their climatic effects. The primary detection methods are the optical method, the thermal–optical method, the thermochemical method, and the single-particle soot photometer method. However, few studies have systematically compared the results of BC and this study found that concentrations of BC in different types of snow and ice varied by 1–3 orders of magnitude, which drastically affected the regional hydrologic process by potentially accelerating the ablation of glaciers by approximately 15% and reducing the duration of snow accumulation by 3–4 days. In general, results obtained from the various testing methods differ drastically, which limited the systematical discussion. Accordingly, a universal standard for the sampling and measurement should be considered in the future work, which will be beneficial to facilitate the comparison of the spatiotemporal features and to provide scientific data for the model-simulated climatic effects of BC. [ABSTRACT FROM AUTHOR]

Investigating the characteristics and transformation of water-soluble carbonaceous matter in the cryosphere regions is important for understanding biogeochemical process in the earth system. Water-soluble carbonaceous matter is a heterogeneous mixture of organic compounds that is soluble in aquatic environments. Despite its importance, we still lack systematic understanding for dissolved organic carbon (DOC) in several aspects including exact chemical composition and physical interactions with microorganisms, glacier meltwater. This review presents the chemical composition and physical properties of glacier DOC deposited through anthropogenic emission, terrestrial, and biogenic sources. We present the molecular composition of DOC and its effect over snow albedo and associated radiative forcings. Results indicate that DOC in snow/ice is made up of aromatic protein-like species, fulvic acid-like materials, and humic acid-like materials. Light-absorbing impurities in surface snow and glacier ice cause considerable albedo reduction and the associated radiative forcing is definitely positive. Water-soluble carbonaceous matter dominated the carbon transport in the high-altitude glacial area. Owing to prevailing global warming and projected increase in carbon emission, the glacial DOC is expected to release, which will have strong underlying impacts on cryosphere ecosystem. The results of this work have profound implications for better understanding the carbon cycle in high altitude cryosphere regions. A new compilation of globally distributed work is required, including large-scale measurements of glacial DOC over high-altitude cryosphere regions, to overcome and address the scientific challenges to constrain climate impacts of light-absorbing impurities related processes in Earth system and climate models. [ABSTRACT FROM AUTHOR]

The unique geographic location of Mt. Yulong in the Tibetan Plateau (TP) makes it a favorable site for mercury (Hg) study. Various snow samples, such as surface snow, snow pit, and snowmelt water were collected from Mt. Yulong in the southeastern TP. The average concentration of Hg was found to be 37 ± 26 ng L−1 (mean ± SD), comparable to Hg concentration from other parts of TP in the same year, though it was comparatively higher than those from previous years, suggesting a possible increase of Hg concentration over the TP. The concentration of Hg was higher in the lower elevation of the glaciers possibly due to the surface melting concentration of particulates. Higher concentration of Hg was observed in the fresh snow, suggesting the possibility of long-range transportation. The average concentration of Hg from the snow pit was 1.49 ± 0.78 ng L−1, and the concentration of Hg in the vertical profile of the snow pit co-varied with calcium ion (Ca2+) supporting the fact that the portion of Hg is from the crustal origin. In addition, the principal component analysis (PCA) confirmed that the source of Hg is from the crustal origin; however, the presence of anthropogenic source in the Mt. Yulong was also observed. In surface water around Mt. Yulong, the concentration of HgT was found in the order of Lashihai Lake > Reservoirs > Rivers > Swamps > Luguhu Lake. In lake water, the concentration of HgT showed an increasing trend with depth. Overall, the increased concentration of Hg in recent years from the TP can be of concern and may have an adverse impact on the downstream ecosystem, wildlife, and human health. [ABSTRACT FROM AUTHOR]

Dissolved organic carbon (DOC) is an important organic pollutant in the air-water carbon cycle system, potentially influencing the global climate. In this study, 204 rainwater samples from five sampling stations in the Mt. Yulong region were synchronously collected from June to September in 2014. We comprehensively investigated the sources and wet deposition of DOC in summer precipitation. The average concentrations of DOC at five stations ranged from 0.74 to 1.31 mg L−1. The mass absorption efficiency (MAE) of rainwater DOC evaluated at 365 nm was 0.43 ± 0.32 m2 g−1. Backward trajectory analyses indicated that the southwest advection air parcel accounting for 46% of precipitation events, while the corresponding average concentration of rainwater DOC was 1.25 ± 0.56 mg C L−1. In addition to the local or regional contribution, large amount of atmospheric pollutants were transported from South Asia and Southeast Asia to the Mt. Yulong region, both of which had exerted great influence on the regional atmospheric environment. For the first time, the annual wet deposition of DOC in the Mt. Yulong region was estimated and determined to be 1.99 g C m−2 year−1. This is significant because the deposition of DOC on glaciers has great influence on surface albedo of snow and glacier melt. This study can bridge the gap of rainwater DOC research between the Mt. Yulong region and the southeast of Tibetan Plateau (TP), which has significant implications for better understanding the relationship of DOC deposition and glacial shrink in the TP. [ABSTRACT FROM AUTHOR]

The snow and ice in Mt. Yulong offer a unique opportunity to investigate changes in climate and large scale atmospheric circulations over Asia. During February and April 2012, surface snow samples were collected from the Baishui Glacier No. 1 at different altitudes along the eastern slope of Mt. Yulong. Two snowpits were also excavated from Mt. Yulong at altitudes of 4780 and 4730 m a.s.l. in February 2012. The concentrations of inorganic ions were higher at an elevation of 4506 m a.s.l. in the glacier with significant contribution of anthropogenic (mainly NH $_{4}^{\mathrm {+}}$ , SO $_{4}^{\mathrm {2-}}$ , NO $_{3}^{\mathrm {-}})$ and crustal (mainly Ca ) constituents. Concentration of HCOO in surface snow exhibited large variability, ranging from 0.04 to 6.8 μeq L , attributed to dominant contribution from biomass burning emissions. Ion balance (ΔC) and Na /Cl calculations indicated an excess of cations (particularly higher Ca concentrations) and Cl in snow, considering the sea-salt ratio, respectively. Monsoon season (June-September) ion concentrations in snowpit samples were generally two-fold lower than in other seasons. Principal component analysis was used to identify different sources of ions. Three main factors, accounting for more than 80% of the total variance, were related to different sources, including agricultural activities, biomass burning, and crustal aerosols. [ABSTRACT FROM AUTHOR]

The present study investigated the chemical composition of summer precipitation at different altitudes in Yulong Snow Mountain, hoping to obtain some basic information about the chemical characteristics of precipitation. A couple of precipitation samples at different altitudes in the Yulong Snow Mountain area in southeastern China were collected from July 26 to July 31, 2005 for chemical analyses. Sea-salt tracer analysis showed that Cl and Na had high proportion from marine sources, while the other ions mainly were from non-marine sources. Statistics showed that the cation concentrations ranged from 0.51 to 5.26 mg L and anion concentrations ranged from 0.99 to 4.90 mg L. Further analysis showed that terrestrial ions, especially from the proximal terrestrial sources, largely affected the ion concentrations in precipitation. Ion concentrations of precipitation were correlated significantly with local atmospheric circulation at altitude 2,950-4,800 m, and also correlated closely with human activities at altitude 2,400-2,950 m. Limestone, the majority of local rocks, caused high cation concentrations in precipitation, such as Ca and Mg. The majority of vapors in the region came from the Indian Ocean whereas parts came from the eastern Pacific. The inorganic ions in precipitation increased significantly in the Yulong Snow Mountain area during this century. Compared with most of the high altitude Mountains in China, the precipitations in the Yulong Snow Mountain area had higher concentrations of inorganic ions and low acidic ion concentrations. The conclusions can provide a basis for study of regional climate characteristics, environment and ecological characteristics of Yulong Snow Mountain area. [ABSTRACT FROM AUTHOR]

The accumulation and ablation of a glacier directly reflect its mass income and wastage, and ice temperature indicates glacier's climatic and dynamic conditions. Glaciological studies at Baishui Glacier No.1 in Mt. Yulong are important for estimating recent changes of the cryosphere in Hengduan Mountains. Increased glacier ablation and higher ice temperatures can cause the incidents of icefall. Therefore, it is important to conduct the study of glacier mass balance and ice temperature, but there are few studies in relation to glacier's mass balance and active-layer temperature in China's monsoonal temperate glacier region. Based on the field observations of mass balance and glacier temperature at Baishui Glacier No.1, its accumulation, ablation, net balance and near-surface ice temperature structure were analyzed and studied in this paper. Results showed that the accumulation period was ranged from October to the following mid-May, and the ablation period occurred from mid-May to October, suggesting that the ablation period of temperate glacier began about 15 days earlier than that of continental glaciers, while the accumulation period began about 15 days later. The glacier ablation rate was 6.47 cm d at an elevation of 4600 m between June 23 and August 30, and it was 7.4 cm d at 4800 m between June 26 and July 11 in 1982, moreover, they respectively increased to 9.2 cm d and 10.8 cm d in the corresponding period and altitude in 2009, indicating that glacier ablation has greatly intensified in the past years. The temperature of the main glacier body was close to melting point in summer, and it dropped from the glacier surface and reached a minimum value at a depth of 4-6 m in the ablation zone. The temperature then rose to around melting point with the depth increment. In winter, the ice temperature rose gradually with the increasing depth, and close to melting point at the depth of 10 m. Compared with the data from 1982, the glacier temperature has risen in the ablation zone in recent decades. [ABSTRACT FROM AUTHOR]

This study focused on the chemical compositions of the rivers around Yulong Mountain, one of the typical monsoonal temperate glacier regions in China. Water samples were collected from Baishui, Sanshu and Geji hydrological stations around Mt. Yulong during rainy season. The chemical analyses indicated that the river water around Mt. Yulong was characterized by high pH values (>8.0) and EC values varied from 36.4 to 71.7 μS/cm with an average of 52.6 μS/cm. Ca and Mg were the dominant cations, together accounting for about 90 % of the total cations. HCO, followed by SO, was the dominant anion. Obvious variations had been perceived during the rainy season. River water chemistry in rainy season was mainly influenced by precipitation and rock weathering. The proportions of Na, K, Ca, Mg and SO from precipitation in river water were 23.44, 9.66, 3.10, 17.81 and 10.48 %, respectively. In addition, the ion characteristics of river water were mainly influenced by carbonate weathering. The human activities should not be ignored though its influence was little. [ABSTRACT FROM AUTHOR]