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The Tibetan Plateau and its surroundings have recently experienced several catastrophic glacier-related disasters. It is of great scientific and practical significance to establish ground-based early warning systems (EWS) to understand the processes and mechanisms of glacial disasters and warn against potential threats to downstream settlements and infrastructure. However, there are few sophisticated EWSs on the Tibetan Plateau. With the support of the Second Tibetan Plateau Scientific Expedition and Research Program, an EWS was developed and implemented in the Sedongpu Valley, southeastern Tibetan Plateau, where repeated river blockages have occurred due to ice/rock collapse debris flow. The EWS collected datasets of optical/thermal videos/photos, geophone waveforms, water levels, and meteorological variables in this sparsely populated zone. It has successfully warned against three ice-rock collapse-debris flow - river blockage chain events and seven small-scale ice-rock collapse-debris flow events. Meanwhile, it was found that the low-cost geophone can effectively indicate the occurrence and magnitude of ice/rock collapses by local thresholds, and water level observation is an efficient way to warn of river blockages. Our observations showed that several factors, such as the volume and location of the collapses and the percentage of ice content involved, influence the velocities of debris flows and the magnitude of river blockages. There are still two possible glaciers in the study area that are at risk of ice collapse. It is worth monitoring their dynamic changes using high-resolution satellite data and the ground-based EWS to safeguard the surrounding hydrological projects and infrastructure in this transboundary region.

Exploring the snow thickness at the Mount Everest has long been a topic of interest for studying geodesy, cryosphere and climate change, but has not yet been measured successfully. Here, we report the ground-penetrating radar survey of snow thickness along the northern slope of the Mount Everest in May 2022. Our radar measurements display a gradual increasing transition of snow thickness along the north slope, and the mean snow thickness estimates at the Mount Everest is approximately 9.5 m. This updated snow thickness at the Mount Everest is much deeper than previously reported values (0.9~3.5 m).

Glacial chronology is critical to the reconstruction of former glaciers. The West Kunlun Mountains represent one of the most important areas for understanding the response of glacier to climate change in regions dominated by the Westerlies. However, accurate chronologies for Quaternary glaciations in this area are still lack. In this work, we identified two sets of moraines at the eastern side of the Guliya ice cap in the West Kunlun Mountains and constrained their emplacement times using the cosmogenic 10Be exposure dating method. The outer moraine set, within ~6 km in front of the modern glaciers, was dated to 231.8 ± 14.7 ka ago, and the inner moraine set, within ~3.5 km downstream of the modern glaciers, was dated to 113.7 ± 7.0 ka ago. This suggested that two glacier advances could have occurred during the marine isotope stages (MIS) 8–7 and MIS 6–5, respectively, and the glaciers became progressively less extensive between these two glacial periods at the eastern side of the Guliya ice cap. Comparing our dating results with previous studies in the Gurla Mandhata, the Tashkurgan Valley, the Muztag Ata and Kongur Shan, we concluded that regional aridification was the most likely explanation for the progressively less extent of the two glacier advances in the western Tibetan Plateau regions.

The Second Tibetan Plateau Scientific Expedition and Research Program (“STEP Program”) has made significant progress in the world’s most influential frontier sciences. Based on the STEP Program, scientists are able to conduct theoretical and practical earth system science research that is fundamental to implementing exemplary solutions to basin protection (e.g., of atmosphere, water, and soil), restoration (e.g., of construction-disturbed areas, ecosystem degradation), and governance (e.g., of water environment degradation, land desertification, and soil erosion), particularly across ecologically fragile high-altitude areas. The Lhasa River Basin, located in the social and economic heartland of Tibet, encompasses the six spheres of earth system science and has been subjected to the dual substantial environmental impact from natural climate changes and human activities. Therefore, it is important to conduct fundamental applied scientific research on the protection, restoration, and governance of natural process-prevalent areas, natural process-human activity overlapping areas, and human activity areas. In this study, the Chabalang small watershed, a typical tributary in the Lhasa River Basin, was selected as the research object, and the effect of the early comprehensive governance demonstration area construction on the ecological environment of the watershed was systematically evaluated. The results showed that during the construction of the comprehensive demonstration area from 2010 to 2012, although the regional precipitation was low, the vegetation coverage in the basin significantly improved because of a series of engineering measures such as slope-to-terrace, artificial planting, and water diversion irrigation. The areas of severe soil erosion and mild soil erosion in the basin were also slightly reduced, according to the soil erosion intensity data for 2005 and 2015. There are several problems in the comprehensive demonstration area, such as lack of systematic observation (e.g., only automatic meteorological observation and slope runoff observation), lack of basic scientific research (e.g., the process and mechanism of runoff and sediment generation are unclear), lack of effective management (e.g., the equipment for automatic meteorological observation and artificial simulated rainfall observation are seriously damaged), and lack of comprehensive restoration and governance integration (e.g., the restoration and governance are scattered and disordered because of being conducted by different departments). Considering the existing problems in the comprehensive demonstration area, we propose a scientific solution to improve the scientific scheme of watershed protection, restoration, and governance. The technology system for protection, restoration, and governance in the Chabalang small watershed should include the protection of the atmosphere, water, and soil, the restoration of construction-disturbed areas and ecosystem degradation, the governance of water environment degradation, land desertification, and soil erosion. We present the following suggestions: improving the system of observation, research, and technology demonstration in the basin, strengthening the basic scientific research, establishing a multi-department coordination mechanism, and strengthening the application and popularisation of technology demonstration systems from the basin to the Tibetan Plateau. This will fill the gap in multi-dimensional observation research and provide a reference for the ecological environment of the Tibetan Plateau.

Glaciers on the Tibetan Plateau (TP) are reliable water sources for Asia. Continuously high-resolution and high-accuracy long-term glacier fluctuations have been examined to improve the reliability of predictions regarding future TP glacier behavior under global climate change. In this study, we analyzed physiochemical parameters in typical glaciolacustrine sediments to reconstruct multidecadal activities of the monsoonal Qiangyong Glacier over the past ~2500 years. The results show that the glacier advanced most strongly during 560 BC–AD 100, followed by AD 1050–1850 and AD 600–850. It retreated most severely during AD 1850–present, followed by AD 100–600 and AD 850–1050. This continuous record corresponds well with changes in the temperature and regional precipitation before the Current Warm Period, exhibiting “warm-humid-retreat” and “cold-dry-advance” patterns. This indicates that temperature changes, rather than precipitation variations, control the monsoonal glaciers at the southern TP at multidecadal to centennial scales. As global warming continues, although the precipitation on the southern TP is projected to increase, the mass loss of TP monsoonal glaciers is expected to continue.

The δ18O of gaseous oxygen in ice core air bubbles (δ18Obub) has been widely used for reconstruction of climate changes in polar glaciers. Yet, less is known about its climatic implication in alpine glaciers as the lack of continuous record. Here, we present a long-term δ18Obub record from the Tanggula glacier in the central Tibetan Plateau (TP). It shows that there is a good correlation between the variation of the δ18Obub in this alpine ice core and the accumulation or melting of the glacier. The more developed the firn layer on glacier surface, the more positive the δ18Obub is. The more intense the glacier melting, the more negative the δ18Obub is. Combined with the chronology of the ice core air bubbles, we reconstructed the glacier variations since the late Holocene in the central TP. It showed that there were four accumulation and three deficit periods of glaciers in this region. The strongest glacier accumulation period was from 1610–300 B.C., which corresponding to the Neoglaciation. The most significant melting period was the last 100 years, which corresponding to the recent global warming. During the Little Ice Age, glacier accumulation in the central TP was not significant, and even short deficit events occurred. Comparisons of the late Holocene glacier variation in the central TP with hemispheric glacier and climate variations showed that it was closely related to the North Atlantic Oscillation.

Glacier collapse is a fairly new type of glacier-related disasters on the Asian Water Towers (AWTs) in the warming climate. On 16 October and 29 October 2018, two glacier collapses occurred in the Sedongpu Basin, 7 km downstream from Gyala Village, Paizhen Town, Miling County, on the Yarlung Tsangpo River (YTR). The ice and entrained debris flows caused by the glacier collapses blocked the YTR, resulting in a potential threat to residents and transport lines upstream and downstream. Through post-event field investigations with a helicopter and an unmanned aerial vehicle (UAV), remote sensing interpretation, and seismic, hydrological, and meteorological observations, the process and potential mechanisms of the glacier collapse-induced river blocking (GCRB) disasters were investigated. We confirmed that the first glacier collapse event occurred at 22:48 (Beijing time) on 16 October 2018 and the second began at 08:03 on 29 October 2018. Approximately 130 × 106 m3 of ice and debris detached from the glacier during the glacier collapse, and we calculated that the river blocking fans caused by the first and second glacier collapse event covered ~1.36 km2 and ~ 1.29 km2 on the main watercourse of the YTR, respectively. We determined that the GCRB incidents represent a disaster chain of glacier collapse → glacial debris flow → river blockage → dammed lake → outburst flood. These incidents arise due to a combination of factors, including glacier activity, climate warming, heavy precipitation, pre-seismic activity, and high topographic relief. In the context of climate warming on the Tibetan Plateau, such glacier collapse induced disaster chains will continue or even intensify in the future. To protect against glacier collapse disasters in the Grand Canyon on the YTR, we established a monitoring and early warning system (EWS), which has already successfully sounded alerts for GCRB incidents. As a major element of an integrated risk management strategy, the EWS represents a viable and promising tool for mitigating climate change-related risks.

Supplemental material, sj-pdf-1-hol-10.1177_09596836211003209 for Late-Holocene fluctuations of monsoonal Qiangyong Glacier, southern Tibetan Plateau by Xiaolong Zhang, Baiqing Xu, Jiule Li, Ying Xie and Gerd Gleixner in The Holocene

The dating of well-preserved Holocene moraines in the Qiangyong Valley, southern Tibetan Plateau (TP), offers great potential for reconstructing Holocene glacier extents and examining climate changes in the region. Guided by Holocene moraine features, this study used Geographic Information System (GIS) model tools to reconstruct paleo-glacier surfaces and glacier equilibrium line altitude (ELA) depressions for three Holocene glacial stages in the valley. The GIS-based models showed that the Qiangyong Valley contained ice volumes of 8.1 &times, 108, 6.2 &times, 108, and 4.6 &times, 108 m3 during the early Holocene, Neoglacial, and Little Ice Age (LIA) glacial stages, and that the ELA was decreased by ~230 &plusmn, 25, ~210 &plusmn, 25, and ~165 &plusmn, 25 m, respectively, compared to modern conditions. Furthermore, the summer temperatures were estimated to be 1.56&ndash, 1.79, 1.37&ndash, 1.64, and 1.29&ndash, 1.32 &deg, C cooler than present to support the three Holocene glacier extents, based on the evidence that the respective precipitation increased by 20&ndash, 98, 13&ndash, 109, and 0.9&ndash, 11 mm relative to the present, which were derived from the lacustrine pollen data for the southern TP. By comparison, this study found that the amplitudes of the ELA-based summer temperature depressions were much larger than the pollen-based counterparts for the three glacial stages, although the two proxies both showed increasing trends in the reconstructed summer temperatures.

Improved daily precipitation and temperature data at 5 x 5-km grids for 1960-2015 were developed for the Upper Yarkant basin (UYB) based on observations of precipitation gradients and temperature lapse rates. The developed climate data are then used to drive the VIC-Glacier hydrological model to simulate the runoff process for the UYB. A large altitudinal dependence is observed in both precipitation and temperature, with three altitudinal patterns of precipitation gradient for the elevation bands of 3,000 m, respectively, and a strong seasonal variation in temperature lapse rate ranging from 0.4 to 0.8 degrees C/100 m. Basin precipitation and temperature data are greatly improved in both amount and spatial variations after the orographic adjustments. Glacier melt runoff is the dominant water source of the UYB accounting for about 52% of annual total flows, followed by snowmelt (about 26%), and rainfall runoff (about 22%). About 60% of basin runoff originates from the high altitudes (>5,000 m), and about 32% and 8% of runoff originate from middle (4,000-5,000 m) and low (

Glaciers on the Tibetan Plateau (TP) exist in different states of extension and retreat, responding to the westerly winds and Indian monsoon. However, few studies to-date have focused on climate change in the westerlies dominated northwest TP. Here, we report an ice core climate record during the last century retrieved from the Kuokuosele (KKSL) Glacier in the westerlies-dominated eastern Pamir, northwest TP. The ice core has dated based on annual layer counting using ice core delta O-18 seasonal cycles, constrained by both the beta (beta) activity peak and Cs-137 concentration peak in 1962/63. Reconstruction of delta O-18 and annual accumulation from the ice core and comparison with observed temperature and precipitation at nearby meteorological stations as well as CRU (Climate Research Unit) data confirm their climatic and regional significance. Both ice core delta O-18 and accumulation increased during the last century, thus pointing to a warming and wetting trend in the westerlies dominated northwest TP.

A Gram-stain-negative, rod-shaped, bacterial strain, B448-2T, was isolated from an ice core from the Muztagh Glacier, on the Tibetan Plateau. B448-2T grew optimally at pH 7.0 and 20 °C in the presence of 0–1.0 % (w/v) NaCl. The results of 16S rRNA gene sequence similarity analysis indicated that B448-2T was closely related to Massilia eurypsychrophila CGMCC 1.12828T, Rugamonas rubra CCM3730T and Duganella zoogloeoides JCM20729T at levels of 97.8, 97.7 and 97.3 %, respectively. The predominant fatty acids of B448-2T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The predominant isoprenoid quinone was Q-8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The genomic DNA G+C content of the strain was 66.1 mol%. In DNA–DNA hybridization tests, B448-2T shared 37.6 % DNA–DNA relatedness with Massilia eurypsychrophila CGMCC 1.12828T. On the basis of the results for phenotypic and chemotaxonomic characteristics, B448-2T was considered to represent a novel species of the genus Massilia , for which the name Massilia glaciei sp. nov. is proposed. The type strain is B448-2T (=JCM 30271T=CGMCC 1.12920T).

Variations in the Indian Monsoon (IM) and Westerlies (WS) significantly affect the climate on the Tibetan Plateau (TP) and have widespread ecological and socioeconomic impacts on the whole of Asian society. So far, however, the rate and magnitude of changes in the IM have still remained unclear. Here we report for the first time that the IM rapidly shifted northward at the end of the Little Ice Age (LIA). We used sediment proxies for humidity and moisture sources from the Taro Co lake, which is located in the transition zone between the WS and IM. Our comprehensive survey of climate records for the TP and its peripheral mountain ranges revealed that the northern boundary of the IM (i.e., the southern boundary of the WS) lay along the southern slope of the Gandise Range (~29.5° N) in the late LIA. In contrast, it passed quickly over the Gandise Range by at least 1.5° in latitude at the end of the LIA. Our results suggest that this rapid climatic shift was potentially triggered by the counteracting effects of blocking by the TP and its marginal orography, which hindered the northward movement of the IM, and the pulling thermal gradient of the TP.

Empirical evidence suggested that the altitudinal dependence of hydrogen isotope ratios of leaf wax n -alkanes ( δ D wax ) can be used to estimate paleoaltitudinal changes. However, the application of δ D wax -based paleoaltimetry remains difficult, as the impacts of evaporative, transpirative and biosynthetic processes on hydrogen isotope fractionations in changing environments and the influence of likely changing water vapor sources are not well explored. For this study, we sampled stream waters, soils and plant leaves along two transects spanning large gradients of altitude, precipitation amount, vapor source, temperature and vegetation type on the Tibetan Plateau (TP). δ D values of stream water (as an approximation for δ D p ), soil water ( δ D sw ) and plant leaf water ( δ D lw ) as well as leaf wax n -alkanes were measured in order to quantify isotopic fractionations in the formation of leaf waxes. Most interestingly, we found a strong negative correlation between the evapotranspirative enrichment of leaf water against precipitation (e lw-p ), which combines the effects of soil evaporation and leaf transpiration, and the biosynthetic hydrogen isotope fractionation (e wax-lw ), which describes isotopic enrichment between leaf wax and leaf water. The relationship yields a steady apparent isotopic enrichment factor (e wax-p ) between leaf wax and precipitation, which is independent from climatic parameters and has an average value of −107 ± 26‰ for grasses (monocotyledons) and −77 ± 22‰ for trees (dicotyledons). Since the terrestrial n -alkanes, especially n -C 27 and n -C 29 , in sediments are derived from trees and grasses, the likely change of the vegetation type in the uplift of mountains can change the isotopic estimates by about ±30‰, which corresponds to an altitudinal change of ∼1600 m. We, therefore, suggest that hydrogen isotope ratio of sedimentary n -C 31 alkane, which is mainly derived from grasses might be better proxies to reconstruct paleoaltitudes. Our large dataset of δ D wax from trees and grasses that aimed to mirror the variability of environmental factors over geological time frames showed the lapse rates were significant, but much smaller than in previous studies. Most importantly our result demonstrated that the lapse rate significantly differed for both transects ( p = 0.0068), i.e. 0.87 ± 0.71‰/100 m ( R 2 = 0.28, p = 0.2841, n = 6) and 2.28 ± 0.82‰/100 m ( R 2 = 0.34, p = 0.0135, n = 17) for Indian monsoon and Westerly dominated areas, respectively. This suggests that different moisture sources might strongly affected the observed lapse rates. In consequences altitude reconstructions are strongly complicated in areas with likely changing air masses like the Tibetan Plateau.

A bacterial strain, B5-2T, was isolated from an ice core drilled from Muztagh Glacier, China. Strain B5-2T was a Gram-stain-negative, short rod-shaped, motile by polar flagella, aerobic bacterium. The major fatty acids of strain B5-2T were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and iso-C13 : 0. The G+C content of the DNA from strain B5-2T was 69.3 mol%. The predominant isoprenoid quinone of strain B5-2T was Q-10. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, an unidentified phospholipid and sulfoquinovosyldiacylglycerol. Comparative 16S rRNA gene sequence analysis revealed that the novel strain B5-2T shared highest similarity (96.7 %) with Aureimonas altamirensis S21BT. On the basis of the results of this polyphasic study, strain B5-2T represents a novel species of the genus Aureimonas, for which the name Aureimonas glaciei sp. nov. is proposed. The type strain is B5-2T (=CGMCC 1.15493T=KCTC 52395T).

Climatic significance of ice core stable isotope record in the Himalayas and southern Tibetan Plateau (TP), where the climate is alternately influenced by Indian summer monsoon and mid-latitude westerlies, is still debated. A newly drilled Zuoqiupu ice core from a temperate maritime glacier on the southeastern TP covering 1942–2011 is investigated in terms of the relationships between δ18O and climate parameters. Distinct seasonal variation of δ18O is observed due to high precipitation amount in this area. Thus the monsoon (June to September) and non-monsoon (October to May) δ18O records are reconstructed, respectively. The temperature effect is identified in the annual δ18O record, which is predominantly contributed by temperature control on the non-monsoon precipitation δ18O record. Conversely, the negative correlation between annual δ18O record and precipitation amount over part of Northeast India is mostly contributed by the monsoon precipitation δ18O record. The variation of monsoon δ18O record is greatly impacted by the Indian summer monsoon strength, while that of non-monsoon δ18O record is potentially associated with the mid-latitude westerly activity. The relationship between Zuoqiupu δ18O record and Sea Surface Temperature (SST) is found to be inconsistent before and after the climate shift of 1976/1977. In summer monsoon season, the role of SST in the monsoon δ18O record is more important in eastern equatorial Pacific Ocean and tropical Indian Ocean before and after the shift, respectively. In non-monsoon season, however, the Atlantic Multidecadal Oscillation has a negative impact before but positive impact after the climate shift on the non-monsoon δ18O record.

High temporal resolution measurements of black carbon (BC) and organic carbon (OC) covering the time period of 1956–2006 in an ice core over the southeastern Tibetan Plateau show a distinct seasonal dependence of BC and OC with higher respective concentrations but a lower OC / BC ratio in the non-monsoon season than during the summer monsoon. We use a global aerosol-climate model, in which BC emitted from different source regions can be explicitly tracked, to quantify BC source–receptor relationships between four Asian source regions and the southeastern Tibetan Plateau as a receptor. The model results show that South Asia has the largest contribution to the present-day (1996–2005) mean BC deposition at the ice-core drilling site during the non-monsoon season (October to May) (81%) and all year round (74%), followed by East Asia (14% to the non-monsoon mean and 21% to the annual mean). The ice-core record also indicates stable and relatively low BC and OC deposition fluxes from the late 1950s to 1980, followed by an overall increase to recent years. This trend is consistent with the BC and OC emission inventories and the fuel consumption of South Asia (as the primary contributor to annual mean BC deposition). Moreover, the increasing trend of the OC / BC ratio since the early 1990s indicates a growing contribution of coal combustion and/or biomass burning to the emissions. The estimated radiative forcing induced by BC and OC impurities in snow has increased since 1980, suggesting an increasing potential influence of carbonaceous aerosols on the Tibetan glacier melting and the availability of water resources in the surrounding regions. Our study indicates that more attention to OC is merited because of its non-negligible light absorption and the recent rapid increases evident in the ice-core record.

A psychrophilic, Gram-stain-negative, rod-shaped, red-pigmented bacterium, designated strain B1789T, was isolated from an ice core of Muztagh Glacier on the Tibetan Plateau in China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B1789T was related to members of the genus Hymenobacter and had highest sequence similarity with Hymenobacter antarcticus JCM 17217T (97.9 %). The major menaquinone was MK-7 and the major polar lipid was phosphatidylethanolamine. The predominant fatty acids were iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The DNA G+C content was 59.4 mol%. In DNA–DNA hybridization tests, strain B1789T shared 42 % relatedness with H. antarcticus JCM 17217T. Based on the results of phenotypic and chemotaxonomic tests, strain B1789T was considered as representing a novel species of the genus Hymenobacter , for which the name Hymenobacter frigidus sp. nov. is proposed. The type strain is B1789T (=JCM 30595T=CGMCC 1.14966T).

Studies have been devoted to the transport and accumulation of persistent organic pollutants (POPs) in mountain environments. The Himalayas have the widest altitude gradient of any mountain range, but few studies examining the environmental behavior of POPs have been performed in the Himalayas. In this study, air, soil, and leaf samples were collected along a transect on the southern slope of the Himalayas, Nepal (altitude: 135–5100 m). Local emission occurred in the lowlands, and POPs were transported by uplift along the slope. During the atmospheric transport, the HCB proportion increased from the lowlands (20%) to high elevation (>50%), whereas the proportions of DDTs decreased. The largest residue of soil POPs appeared at an altitude of approximately 2500 m, and may be related to absorption by vegetation and precipitation. The net deposition tendencies at the air–soil surface indicated that the Himalayas may be a ‘sink’ for DDTs and PCBs.

HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that reactions with the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect atmospheric HOx concentrations and chemistry.

A Gram-stain-negative, non-motile, reniform bacterial strain, B2974T, was isolated from an ice core of the Muztagh Glacier, on the Tibetan Plateau, China. Strain B2974T grew optimally at pH 7.0–7.5 and 25–30 °C in the presence of 0–2.0 % (w/v) NaCl. 16S rRNA gene sequence similarity analysis indicated that strain B2974T was closely related to Chelatococcus asaccharovorans LMG 25503T at a level of 97.1 %. The major quinone of strain B2974T was ubiquinone Q10. The predominant fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C19 : 0 cyclo ω8c. sym-Homospermidine was the major polyamine. The genomic DNA G+C content of the strain was 64 mol%. In DNA–DNA hybridization tests, strain B2974T shared 49.32 % DNA–DNA relatedness with the type strain of Chelatococcus asaccharovorans LMG 25503T. Based on the results of phenotypic and chemotaxonomic characteristics, strain B2974T was considered as a novel species of the genus Chelatococcus , for which the name Chelatococcus reniformis sp. nov. is proposed. The type strain is B2974T (=JCM 30308T=CGMCC 1.12919T).

A Gram-stain-negative, aerobic, rod-shaped, motile bacterium, strain B1555-1T, was isolated from an ice core drilled from Ulugh Muztagh Glacier, China. The optimum growth temperature of strain B1555-1T was 15 °C and optimum pH was 7. The major fatty acids of strain B1555-1T were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The predominant respiratory quinone was Q-8. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content of strain B1555-1T was 66.0 mol%. In 16S rRNA gene sequence comparisons, strain B1555-1T was affiliated to the genus Massilia and shared 98.30 and 97.13 % similarity with Massilia eurypsychrophila B528-3T and Massilia niabensis 5420S-26T, respectively. The results of DNA–DNA hybridization revealed that strain B1555-1T showed 49.8 % relatedness with M. eurypsychrophila B528-3T and 38.5 % with M. niabensis 5420S-26T. Based on the genotypic and phenotypic evidence presented in this study, strain B1555-1T represents a novel species of the genus Massilia , for which the name Massilia psychrophila sp. nov. is proposed. The type strain is B1555-1T (=CGMCC 1.15196T=JCM 30813T).

Organic tracer compounds, as well as organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and stable carbon isotope ratios (δ13C) of total carbon (TC) have been investigated in aerosol samples collected during early and late periods of the Mount Tai eXperiment 2006 (MTX2006) field campaign in the North China Plain. Total solvent-extractable fractions were investigated by gas chromatography/mass spectrometry. More than 130 organic compounds were detected in the aerosol samples. They were grouped into twelve organic compound classes, including biomass burning tracers, biogenic primary sugars, biogenic secondary organic aerosol (SOA) tracers, and anthropogenic tracers such as phthalates, hopanes and polycyclic aromatic hydrocarbons (PAHs). In early June when the field burning activities of wheat straws in the North China Plain were very active, the total identified organics (2090 ± 1170 ng m−3) were double those in late June (926 ± 574 ng m−3). All the compound classes were more abundant in early June than in late June, except phthalate esters, which were higher in late June. Levoglucosan (88–1210 ng m−3, mean 403 ng m−3) was found as the most abundant single compound in early June, while diisobutyl phthalate was the predominant species in late June. During the biomass-burning period in early June, the diurnal trends of most of the primary and secondary organic aerosol tracers were characterized by the concentration peaks observed at mid-night or in early morning, while in late June most of the organic species peaked in late afternoon. This suggests that smoke plumes from biomass burning can uplift the aerosol particulate matter to a certain altitude, which could be further transported to and encountered the summit of Mt. Tai during nighttime. On the basis of the tracer-based method for the estimation of biomass-burning OC, fungal-spore OC and biogenic secondary organic carbon (SOC), we estimate that an average of 24% (up to 64%) of the OC in the Mt. Tai aerosols was due to biomass burning in early June, followed by the contribution of isoprene SOC (mean 4.3%). In contrast, isoprene SOC was the main contributor (6.6%) to OC, and only 3.0% of the OC was due to biomass burning in late June. In early June, δ13C of TC (−26.6 to −23.2‰, mean −25.0‰) were lower than those (−23.9 to −21.9‰, mean −22.9‰) in late June. In addition, a strong anti-correlation was found between levoglucosan and δ13C values. This study demonstrates that crop-residue burning activities can significantly enhance the organic aerosol loading and alter the organic composition and stable carbon isotopic composition of aerosol particles in the troposphere over the North China Plain.

Mixing of Asian mineral dust with anthropogenic pollutants allows pollutants (e.g. sulfate and nitrate) to be transported over longer distances (e.g. to the northern Pacific, even to North America) along with dust particles. This mixing therefore affects the atmospheric and oceanic environment at local, regional and even continental scales. In this study, we used a three-dimensional regional chemical transport model (Nested Air Quality Predicting Modeling System, NAQPMS) to examine the degree of mixing between Asian mineral dust and anthropogenic pollutants in a super-duststorm event during 19–22 March 2010. Influences of the mixing processes on regional atmospheric environmental and oceanic biogeochemical cycles were also investigated. A comparison with measurements showed that the model reproduced well the trajectory of long-range dust transport, the vertical dust profile, and the chemical evolution of dust particles. We found that along-path mixing processes during the long-range transport of Asian dust led to increasingly polluted particles. As a result, ~60% of the sulfate and 70–95% of the nitrate in the downwind regions was derived from active mixing processes of minerals with pollutants sourced from the North China Plain and enhanced by transport over South China. This mixing had a significant impact on the regional-scale atmospheric composition and oceanic biogeochemical cycle. Surface HNO3, SO2 and O3 were decreased by up to 90%, 40% and 30%, respectively, due to the heterogeneous reactions on dust particles. Fe solubility rose from ~0.5% in the Gobi region to ~3–5% in the northwestern Pacific, resulting from oxidization of SO2 on dust particles. Total Fe(II) deposition in the ocean region of East Asia reached 327 tons during the 4-day dust event, and created a calculated primary productivity of ~520 mgC m−2 d−1 in the Kuril Islands, which can support almost 100% of the observed mean marine primary productivity in spring in this region (526 mgC m−2 d−1).

Understanding the relationship between black carbon (BC) and carbon monoxide (CO) will help improve BC emission inventories and the evaluation of global/regional climate forcing effects. In the present work, the BC (PM1) mass concentration and CO mixing ratio were continuously measured at a high-altitude background station on the summit of Mt. Huang (30.16° N, 118.26° E, 1840 m a.s.l.). Annual mean BC mass concentration was 1004.5 ± 895.5 ng m−3 with maxima in spring and autumn, and annual mean CO mixing ratio was 424.1 ± 159.2 ppbv. A large increase of CO was observed in the cold season, implying the contribution from the large-scale domestic coal/biofuel combustion for heating. The BC-CO relationship was found to show different seasonal features but strong positive correlation (R>0.8). In Mt. Huang area, the ΔBC/ΔCO ratio showed unimodal diurnal variations and had a maximum during the day (09:00–17:00 LST) and minimum at night (21:00–04:00 LST) in all seasons, indicating the impact of planetary boundary layer and the intrusion of clean air masses from the high troposphere. Back trajectory cluster analysis showed that the ΔBC/ΔCO ratio of plumes from the Eastern China (Jiangsu, Zhejiang provinces and Shanghai) was 8.8 ± 0.9 ng m−3 ppbv−1. Transportation and industry were deemed as controlling factors of the BC-CO relationship in this region. The ΔBC/ΔCO ratios for air masses from Northern China (Anhui, Henan, Shanxi and Shandong provinces) and southern China (Jiangxi, Fujian and Hunan provinces) were quite similar with mean values of 6.5 ± 0.4 and 6.5 ± 0.2 ng m−3 ppbv−1 respectively. The case studies combined with satellite observations demonstrated that the ΔBC/ΔCO ratio for biomass burning (BB) plumes were 10.3 ± 0.3 and 11.6 ± 0.5ng m−3 ppbv−1, significantly higher than those during non-BB impacted periods. The loss of BC during transport was also investigated on the basis of the ΔBC/ΔCO-RH (relative humidity) relationship along air mass pathways. The results showed that BC particles from Eastern China area was much more easily removed from atmosphere than other inland regions due to the higher RH along transport pathway, implying the importance of chemical compositions and mixing states on BC residence time in the atmosphere.

This study investigates the effects of the total solar eclipse of 22 July 2009 on surface ozone and other photo-oxidants over China. A box model was used to study the sensitivity of ozone to the limb darkening effect during an eclipse event, and to show that the impact on ozone is small (less than 0.5 %). In addition, the regional model WRF-Chem was applied to study the effects of the eclipse on meteorological and chemical parameters, focusing on different regions in China. Chemical and meteorological observations were used to validate the model and to show that it can capture the effects of the total solar eclipse well. Model calculations show distinct differences in the spatial distributions of meteorological and chemical parameters with and without the eclipse. The maximum impacts of the eclipse occur over the area of totality, where there is a decrease in surface temperature of 1.5 °C and decrease in wind speed of 1 m s−1. The maximum impacts on atmospheric pollutants occur over parts of north and east China where emissions are greater, with an increase of 5 ppbv in NO2 and 25 ppbv in CO and a decrease of 10 ppbv in O3 and 4 ppbv in NO. This study also demonstrates the effects of the solar eclipse on surface photo-oxidants in different parts of China. Although the sun was obscured to a smaller extent in polluted areas than in clean areas, the impacts of the eclipse in polluted areas are greater and last longer than they do in clean areas. In contrast, the change in radical concentrations (OH, HO2 and NO3) in clean areas is much larger than in polluted areas mainly because of the limited source of radicals in these areas. The change in radical concentrations during the eclipse reveals that nighttime chemistry dominates in both clean and polluted areas. As solar eclipses provide a natural opportunity to test more thoroughly our understanding of atmospheric chemistry, especially that governed by photolysis, a comprehensive experimental campaign during a future solar eclipse is highly desirable.

Nitric acid (HNO3) or nitrate (NO3−) is the dominant sink for reactive nitrogen oxides (NOx = NO + NO2) in the atmosphere. In many Chinese cities, HNO3 is becoming a significant contributor to acid deposition. In the present study, we measured nitrogen (N) and oxygen (O) isotopic composition of NO3− in 113 precipitation samples collected from Guangzhou City in southern China over a two-year period (2008 and 2009). We attempted to better understand the spatial and seasonal variability of atmospheric NOx sources and the NO3− formation pathways in this N-polluted city in the Pearl River Delta region. The δ15N values of NO3− (versus air N2) ranged from −4.9 to +10.1‰, and averaged +3.9‰ in 2008 and +3.3‰ in 2009. Positive δ15N values were observed throughout the year, indicating the anthropogenic contribution of NOx emissions, particularly from coal combustion. Different seasonal patterns of δ15N-NO3− were observed between 2008 and 2009, which might reflect different human activities associated with the global financial crisis and the intensive preparations for the 16th Asian Games. Nitrate δ18O values (versus Vienna Standard Mean Ocean Water) varied from +33.4 to +86.5‰ (average +65.0‰ and +67.0‰ in 2008 and 2009, respectively), a range being lower than those reported for high latitude and polar areas. Sixteen percent of δ18O values was observed lower than the expected minimum of +55‰ at our study site. This was likely caused by the reaction of NO with peroxy radicals; peroxy radicals can compete with O3 to convert NO to NO2, thereby donate O atoms with much lower δ18O value than that of O3 to atmospheric NO3−. Our results highlight that the influence of human activities on atmospheric chemistry can be recorded by the N and O isotopic composition of atmospheric NO3− in a N-polluted city.

A high-resolution 2000-year methane record has been constructed from an ice core recovered at 7200 m a.s.l. on the Dasuopu Glacier in the central Himalayas. This sub-tropical methane record reveals an increasing trend in the concentration of methane during the industrial era that is similar to observations from polar regions. However, we also observed the differences in the atmospheric methane mixing ratio between this monsoon record and those from polar regions during pre-industrial times. In the time interval 0 ∼ 1850 A.D., the average methane concentration in the Dasuopu ice core was 782±40 ppbv and the maximum temporal variation exceeded 200 ppbv. The difference gradient of methane concentration in Dasuopu ice core with Greenland and Antarctica cores are 66±40 ppbv and 107±40 ppbv, respectively. This suggests that the tropical latitudes might have acted as a major global methane source in preindustrial times. In addition, the temporal fluctuation of the pre-industrial methane records suggests that monsoon evolution incorporated with high methane emission from south Asia might be responsible for the relatively high methane concentration observed in the Dasuopu ice core around A.D. 800 and A.D. 1600. These results provide a rough understanding of the contribution of tropical methane source to the global methane budget and also the relationship between atmospheric methane and climate change.

Using a high-resolution tunable diode laser photoacoustic spectrometer, self-, N 2 and O 2 pressure broadening coefficients for the first 11 transitions of 12 C 16 O 2 in the R branch of the (30012) ← (00001) overtone band at the 6348 cm −1 have been revisited at room temperature (∼298 K). Air-broadening parameters have also been calculated from the N 2 and O 2 measurements. The dependence of the broadening on rotational quantum number m is discussed. The recorded lineshapes are fitted with standard Voigt line profiles in order to determine the collisional broadening coefficients of carbon dioxide transitions. The results are compared to our previous measurements and to the values reported in the HITRAN04 database and by other research group with a different spectroscopic technique.

Pressure-induced foreign-broadening lineshape parameters of the carbon dioxide rovibrational transitions belonging to the (30012)←(00001) overtone band near the 1.573 μm wavelength region are measured by using a tunable diode laser photoacoustic spectrometer. The spectroscopic analysis has concerned the first 11 lines of the R branch. For these lines, the air- and Ar-broadening coefficients are measured at room temperature (∼298 K). The measured broadening coefficients of all the transitions of 12 C 16 O 2 are compared with those given in the HITRAN04 database and former measurements with a different spectroscopic method. Agreements and discrepancies are underlined and briefly discussed. The recorded lineshapes are fitted with standard Voigt line profiles in order to determine the collisional broadening coefficient of carbon dioxide transitions.

We conducted an intensive field campaign at the summit of Mt. Tai (36.26° N, 117.11° E, 1534 m above sea level), Shandong Province, located at the center of central East China, during the period 28 May to 30 June 2006, to study seasonal maxima of regional air pollution with respect to ozone (O3) and aerosols. The specific objectives, campaign design, and major findings are summarized. High concentrations of O3 and its precursors, and aerosols, were detected and studied in the context of annual variations. Most importantly, we identified that emissions from regional-scale open crop residue burning after the harvesting of winter wheat, together with photochemical aging, strongly increased the concentrations of O3, aerosols, and primary pollutants in this month of year. Studies of in situ photochemical activity, regional source attribution of O3, O3–aerosol interactions, validation of satellite observations of tropospheric NO2, behaviors of volatile organic compounds and organic/inorganic aerosol species, loss rates of black carbon (BC), and instrument inter-comparisons are also summarized. The observed BC levels must have a strong impact on the regional climate.

Reliable perennial biomonitoring of airborne polycyclic aromatic hydrocarbons (PAHs) is urgently necessary to detect long-term impacts of anthropogenic emission, in response to industrial policies and combustion technology adoption. One hundred records of airborne PAHs were novelly demonstrated by analyzing the tree-rings of Kwangtung pine (Pinus kwangtungensis) formed from 1883 to 2007 at Naling Mountains of southern China. The total concentrations of PAHs (∑PAHs) detected in the tree xylem did not progressively increase against the time. Temporal increase of high molecular-weight PAHs (HMW-PAHs) coincided well to the historical-socioeconomic status in China, suggesting HMW-PAHs in old trees growing at high mountains were more indicative of regionally historical changes in airborne PAHs compared with ∑PAHs. Compositional analysis indicated airborne PAHs absorbed and accumulated in tree tissues were pyrogenic origination. Principal component analysis revealed PAHs inputs were quite historically diversiform and unevenly distributed in the atmosphere of Nanling Mountains of southern China. Dendroanalysis of old trees grown at geographically sink locations could be a useful biomonitoring technique for unravelling historical changes in PAHs composition and intensity in the atmosphere, in relation to regional industrial development and fuel consumptions.

Primary (i.e., sugars and sugar alcohols) and secondary water-soluble organic compounds (WSOCs) (i.e., dicarboxylic acids and aromatic acids) were characterised on a molecular level in size-segregated aerosols from the urban and mountain atmosphere of China and from the marine atmosphere in the outflow region of East Asia. Levoglucosan is the most abundant WSOCs in the urban and mountain atmosphere, whose accumulated concentrations in all stages are 1–3 orders of magnitude higher than those of marine aerosols. In contrast, malic, succinic and phthalic acids are dominant in the marine aerosols, which are 3–6 times more abundant than levoglucosan. This suggests that a continuous formation of secondary organic aerosols is occurring in the marine atmosphere during the long-range transport of air mass from inland China to the North Pacific. Sugars and sugar-alcohols, except for levoglucosan, gave a bimodal size distribution in the urban and mountain areas, peaking at 0.7–1.1 μm and >3.3 μm, and a unimodal distribution in the marine region, peaking at >3.3 μm. In contrast, levoglucosan and all the secondary WSOCs, except for benzoic and azelaic acids, showed a unimodal size distribution with a peak at 0.7–1.1 μm. Geometric mean diameters (GMDs) of the WSOCs in fine particles (