Black Carbon (BC), as a driver of environmental change, could significantly impact the snow by accelerating melting and decreasing albedo. Systematic documentation of BC studies is crucial for a better understanding of its spatial and temporal trends. This study reviewed the BC studies in the ice core and remote lake sediments and their sources in the northern hemisphere. The literature surveyed points to around 2.9 to 3.7 times increase of BC in the European Alps and up to a three-fold increase of BC in the Himalayan-Tibetan Plateau (HTP) after the onset of industrialization in Europe and Asia, respectively. BC concentration from Greenland ice core showed seven times increase with an interrupted trend after 1950's. South Asian emissions were dominant in the HTP along with a contribution from the Middle East, whereas Western European and local emissions were responsible for the change in BC concentration in the European Alps. In the Arctic, contributions from North America, Europe and Asia persisted. Similarly, a historical reconstruction of lake sediments records demonstrates the effects of emissions from long-range transport, sediment focusing, local anthropogenic activities, precipitation and total input of flux on the BC concentration.

Based on an investigation of four published batches listing 3,140 national intangible cultural heritage (ICH) projects in China and using GIS and some quantitative analysis methods, the spatial structure was investigated and the characteristics and distribution discussed. The distribution of ICHs in China is agglomerative and spatially dependent. From the view of ICH type, each type is distributed in different places, for different reasons, with history being the most important one we found. Nationwide, high-density cores are located in the Beijing-Tianjin-Hebei region and the Yangtze River Delta region. High densities of ICH are concentrated in flat, water-rich regions where broad-leaved forests dominate plains and low mountain areas—areas that have fertile soil, pleasant weather, a long history of culture, ethnic agglomeration, and development. This paper suggests that development of the ICH should be based on discovering unknown items, to break the existing pattern of strong cohesion and high density, and to seek a balanced development of the whole.

As one of the five components of Earth's climatic system, the cryosphere has been undergoing rapid shrinking due to global warming. Studies on the formation, evolution, distribution and dynamics of cryospheric components and their interactions with the human system are of increasing importance to society. In recent decades, the mass loss of glaciers, including the Greenland and Antarctic ice sheets, has accelerated. The extent of sea ice and snow cover has been shrinking, and permafrost has been degrading. The main sustainable development goals in cryospheric regions have been impacted. The shrinking of the cryosphere results in sea-level rise, which is currently affecting, or is soon expected to affect, 17 coastal megacities and some small island countries. In East Asia, South Asia and North America, climate anomalies are closely related to the extent of Arctic sea ice and snow cover in the Northern Hemisphere. Increasing freshwater melting from the ice sheets and sea ice may be one reason for the slowdown in Atlantic meridional overturning circulation in the Arctic and Southern Oceans. The foundations of ports and infrastructure in the circum-Arctic permafrost regions suffer from the consequences of permafrost degradation. In high plateaus and mountainous regions, the cryosphere's shrinking has led to fluctuations in river runoff, caused water shortages and increased flooding risks in certain areas. These changes in cryospheric components have shown significant heterogeneity at different temporal and spatial scales. Our results suggest that the quantitative evaluation of future changes in the cryosphere still needs to be improved by enhancing existing observations and model simulations. Theoretical and methodological innovations are required to strengthen social economies' resilience to the impact of cryospheric change.

The measurement of pile axial load is of great significance to determining pile foundation design parameters such as skin friction and end bearing capacity and analyzing load transfer mechanisms. Affected by the temperature and ice content of frozen ground, the interface contact relationship between pile foundation and frozen soil is complicated, making pile axial load measurements more uncertain than that in non-frozen ground. Therefore, it is necessary to gain an in-depth understanding of the current pile axial load test methods. Four methods are systematically reviewed: vibrating wire sensors, strain gauges, sliding micrometers, and optical fiber strain sensors. At the same time, the applicability of the four test methods in frozen soil regions is discussed in detail. The first two methods are mature and commonly used. The sliding micrometer is only suitable for short-term measurement. While the Fiber Bragg grating (FBG) strain gauge meets the monitoring requirements, the Brillouin optical time-domain reflectometer (BOTDR) needs further verification. This paper aims to provide a technical reference for selecting and applying different methods in the pile axial load test for the stability study and bearing capacity assessment of pile foundations in cold regions.

This work presents a reference system overview to improve the efficiency of biological improvement of saline-alkali soil developed during the last thirty years, ranging from connotation, general methods and species, soil desalination, soil structure, soil organic content, microbial flora, enzyme activity, yield and economic benefits. The reference system presented is divided into three main groups: suitable varieties, suitable cultivation measures, and a comprehensive evaluation system. There has been a lot of research on biological improvement of saline alkali soil, but these studies are very fragmented and lack a comprehensive standard system. Also, there is a lack of practical significance, particularly with regard to optimal species, densities and times of sowing for particular regions. On the other hand, the corresponding cultivation measure is very important. Therefore, a reference system plays an important role to the effect of biological improvement of saline alkali soil.

The soil-freezing characteristic curve (SFCC), which represents the relationship between unfrozen water content and sub-freezing temperature (or suction at ice-water interface) in a freezing soil, can be used for understanding the transportation of heat, water, and solute in frozen soils. In this paper, the soil freezing process and the similarity between the SFCC of saturated frozen soil and soil-water characteristic curve (SWCC) of unfrozen unsaturated soil are reviewed. Based on similar characteristics between SWCC and SFCC, a conceptual SFCC is drawn for illustrating the main features of soil freezing and thawing processes. Various SFCC expressions from the literature are summarized. Four widely used expressions (i.e., power relationship, exponential relationship, van Genuchten 1980 equation and Fredlund and Xing 1994 equation) are evaluated using published experimental data on four different soils (i.e., sandy loam, silt, clay, and saline silt). Results show that the exponential relationship and van Genuchten (1980) equation are more suitable for sandy soils. The simple power relationship can be used to reasonably best-fit the SFCC for soils with different particle sizes; however, it exhibits limitations when fitting the saline silt data. The Fredlund and Xing (1994) equation is suitable for fitting the SFCCs for all soils studied in this paper.

Land surface actual evapotranspiration is an important process that influences the Earth's energy and water cycles and determines the water and heat transfer in the soil-vegetation-atmosphere system. Meanwhile, the cryosphere's hydrological process is receiving extensive attention, and its water problem needs to be understood from multiple perspectives. As the main part of the Chinese cryosphere, the Tibetan Plateau faces significant climate and environmental change. There are active interaction and pronounced feedback between the environment and ET_a in the cryosphere. This article mainly focuses on the research progress of ET_a in the Tibetan Plateau. It first reviews the ET_a process, characteristics, and impact factors of typical underlying surfaces in the Tibetan Plateau (alpine meadows, alpine steppes, alpine wetlands, alpine forests, lakes). Then it compares the temporal and spatial variations of ET_a at different scales. In addition, considering the current greening of cryosphere vegetation due to climate change, it discusses the relationship between vegetation greening and transpiration to help clarify how vegetation activities are related to the regional water cycle and surface energy budget.

Characterizing spatial and temporal variability of soil salinity is tremendously important for a variety of agronomic and environmental concerns in arid irrigation areas.This paper reviews the characteristics and spatial and temporal variations of soil salinization in the Ili River Irrigation Area by applying a geostatistical approach.Results showed that:(1) the soil salinity varied widely,with maximum value of 28.10 g/kg and minimum value of 0.10 g/kg,and was distributed mainly at the surface soil layer.Anions were mainly SO₄^2- and Cl^-,while cations were mainly Na⁺ and Ca²⁺;(2) the abundance of salinity of the root zone soil layer for different land use types was in the following order:grassland >cropland >forestland. The abundance of salinity of root zone soil layers for different periods was in the following order:March >June >September;(3) the spherical model was the most suitable variogram model to describe the salinity of the 0-3 cm and 3-20 cm soil layers in March and June,and the 3-20 cm soil layer in September,while the exponential model was the most suitable variogram model to describe the salinity of the 0-3 cm soil layer in September.Relatively strong spatial and temporal structure existed for soil salinity due to lower nugget effects;and(4) the maps of kriged soil salinity showed that higher soil salinity was distributed in the central parts of the study area and lower soil salinity was distributed in the marginal parts. Soil salinity tended to increase from the marginal parts to the central parts across the study area.Applying the kriging method is very helpful in detecting the problematic areas and is a good tool for soil resources management.Managing efforts on the appropriate use of soil and water resources in such areas is very important for sustainable agriculture,and more attention should be paid to these areas to prevent future problems.

Understanding the effect of biodiversity on ecosystem function is critical to promoting the sustainability of ecosystems and species conservation in natural ecosystems. We observed species composition, species richness and aboveground biomass, and simulated the competitive assemblages in a natural grassland ecosystem of China, aiming to test some assumptions and predictions about biodiversity–stability relationships. Our results show that aboveground productivity and temporal stability increased significantly with increasing species richness, and via a combination of overyielding, species asynchrony, and portfolio effects. Species interactions resulted in overyielding caused by trait-independent complementarity, and were not offset by a negative dominance effect and trait-dependent complementarity effect. Therefore, the mechanisms underlying the biodiversity effect shifted from the selection effect to the complementarity effect as diversity increased, and both effects were coexisted but the complementarity effect represent a mechanism that facilitates long term species coexistence in a natural grassland ecosystem of China.

On the basis of the summer daily-precipitation meteorological data collected from weather stations across Northwest China from 1957 to 2016, this study evaluated the trends in 12-daily precipitation indices in the summer season and their relations with air temperature. Precipitation-event intensity, which was averaged over the total study area, increased in recent decades although the total precipitation continuously decreased. In particular, intensity generally decreased in the northern and eastern parts and increased in the southern and western parts of the study area. None of the 12 precipitation indices was significantly correlated with temperature in Xinjiang; R95N (number of events with precipitation greater than the long-term 95th percentile), RX1day (greatest 1-day total precipitation), PI (simple daily intensity), and R10 (number of heavy-precipitation days) were significantly and positively correlated with temperature in Qinghai–Gansu. However, low correlation coefficients were observed. In the Loess Plateau, P (total precipitation), WS (maximum number of consecutive wet days), R95N, and WD (number of wet days) were significantly and negatively correlated with temperature, whereas Gini (gini concentration index) and DS (maximum number of consecutive dry days) were significantly and positively correlated with temperature. Results of the study suggested that climate shift was evident in terms of daily precipitation, and the study area faced new challenges involving precipitation-event intensity increasing in the southwestern part and unevenly dispersing in the northwest.

An underlying wetland surface comprises soil, water and vegetation and is sensitive to local climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Using data from observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling (Ω factor) between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors (solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows: (1) Due to diurnal variations of solar radiation and wind speed, a trend developed where diurnal variations of the Ω factor were small in the morning and large in the evening. Due to the vegetation growing cycle, seasonal variations of the Ω factor present a reverse "U" trend. These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over latent heat flux. This conforms to the Omega Theory. (2) The values for average absolute atmospheric factor (surface factor or total) control exercised by solar radiation and water vapour pressure are 0.20 (0.02 or 0.22) and 0.005 (?0.07 or ?0.06) W/(m²·Pa), respectively. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on latent heat flux. (3) At the underlying alpine wetland surface, solar radiation primarily influences latent heat flux through its direct effects (atmospheric factor controls). Water vapour pressure deficit primarily influences latent heat flux through its indirect effects (surface factor controls) on changing the surface resistance. (4) The average Ω factor in the underlying alpine wetland surface is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between alpine wetland surface and atmosphere system is low. The actual measurements agree with the Omega Theory. The latent heat flux is mainly influenced by solar radiation.

The measurement of black carbon (BC) and organic carbon (OC), dust in total suspended particulates (TSP) was carried out at Yulong Snow Mountain (Mt. Yulong) and Ganhaizi Basin, in the Mt. Yulong region, southwestern China. TSP samples were analyzed using a thermal/optical reflectance carbon analyzer. Results show that average BC and OC concentrations in TSP in the Mt. Yulong region were 1.61±1.15 μg/m³ and 2.96±1.59 μg/m³, respectively. Statistical results demonstrated that there were significant differences in mean BC and OC contents between Ganhaizi Basin and Mt. Yulong at the 0.05 level. Strong correlations between BC and OC indicate their common dominant emission sources and transport processes. Temporal variations of BC, OC, and optical attenuation (ATN) values were consistent with each other in carbonaceous aerosols. The ratios of OC/BC in monsoon season were significantly higher than in non-monsoon in aerosols from Ganhaizi, which is closely related to the formation of secondary organic carbon (SOC) and extensive motor vehicle emissions from tourism activities. The temporal variations of BC, OC and ATN in carbonaceous aerosols in Ganhaizi and Mt. Yulong were totally different, probably due to elevation difference and diverse tourism activity intensity between the two sites. Time-averaged aerosol optical depth (AOD) at the wavelength of 550 nm in Mt. Yulong was higher than that of the inland of the Tibetan Plateau (TP). Source apportionment indicated that intensive exhaust emissions from tourism vehicles were the main local sources of atmospheric pollutant in the Mt. Yulong region. Biomass-burning emissions released from South Asia could penetrate into the inland of the TP under the transport of summer monsoon. Further study is needed to assess light absorption and radiative forcing of carbonaceous aerosols, and modeling research in combination with long-term in-situ observations of light-absorbing particulates (LAPs) in the TP is also urgently needed in future work.

This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strength properties of coarse-grained soil by means of frost heaving tests and static triaxial tests, and the results are as follows:(1) the freezing temperature of coarse-grained soil decreased gradually and then leveled off with incremental increases in the percent content of fines; (2) the fines content proved to be an important factor influencing the frost heave susceptibility and strength properties of coarse-grained soil. With incremental increases in the percent content of fines, the frost heave ratio increased gradually and the cohesion function of fines effectively enhanced the shear strength of coarse-grained soil before freeze-thaw, but the frost susceptibility of fines weakened the shear strength of coarse-grained soil after freeze-thaw; (3) with increasing numbers of freeze-thaw cycles,the shear strength of coarse-grained soil decreased and then stabilized after the ninth freeze-thaw cycle, and therefore the mechanical indexes of the ninth freeze-thaw cycle are recommended for the engineering design values; and (4) considering frost susceptibility and strength properties as a whole, the optimal fines content of 5% is recommended for railway subgrade coarse-grained soil fillings in frozen regions.

Most previous research on areas with abundant rainfall shows that simulations using rainfall-runoff modes have a very high prediction accuracy and applicability when using a back-propagation (BP), feed-forward, multilayer perceptron artificial neural network (ANN). However, in runoff areas with relatively low rainfall or a dry climate, more studies are needed. In these areas—of which oasis-plain areas are a particularly good example—the existence and development of runoff depends largely on that which is generated from alpine regions. Quantitative analysis of the uncertainty of runoff simulation under climate change is the key to improving the utilization and management of water resources in arid areas. Therefore, in this context, three kinds of BP feed-forward, three-layer ANNs with similar structure were chosen as models in this paper. Taking the oasis–plain region traverse by the Qira River Basin in Xinjiang, China, as the research area, the monthly accumulated runoff of the Qira River in the next month was simulated and predicted. The results showed that the training precision of a compact wavelet neural network is low; but from the forecasting results, it could be concluded that the training algorithm can better reflect the whole law of samples. The traditional artificial neural network (TANN) model and radial basis-function neural network (RBFNN) model showed higher accuracy in the training and prediction stage. However, the TANN model, more sensitive to the selection of input variables, requires a large number of numerical simulations to determine the appropriate input variables and the number of hidden-layer neurons. Hence, The RBFNN model is more suitable for the study of such problems. And it can be extended to other similar research arid-oasis areas on the southern edge of the Kunlun Mountains and provides a reference for sustainable water-resource management of arid-oasis areas.

Ice documentation and response to prominent warming, especially after the 1990s, is further investigated because it is concerned whether ice records have absence. A δ¹⁸O series of a Laohugou (LHG) shallow ice core (20.12 m) in the northeastern Tibetan Plateau was reconstructed covering the period of 1960-2006. The ice core δ¹⁸O record had significant positive correlations with the warm season (May-September) air temperatures at adjacent meteorological stations and the 500 hPa temperatures in boreal China, indicating that the δ¹⁸O record could be considered a credible proxy of regional temperature. A clear, cold temperature event in 1967 and rapid warming after the 1990s were captured in the LHG δ¹⁸O series, revealing that it could record extreme air-temperature events on both regional and global scales. The LHG δ¹⁸O variations had evident positive correlations with both the summer surface outgoing longwave radiation (OLR) in the Mongolia region and the summer meridional wind at 500 hPa in the LHG region during 1960-2006, suggesting that the increased OLR in the Mongolia region might have intensified the Mongolia Low and expanded the pressure gradient to the LHG region (the Shulehe High), which would have pushed the westerlies further north and suppressed southward incursions of cold air into the LHG region, and thus augmented the temperature rise. The regional atmospheric circulation difference (1985-2006 minus 1960-1984) suggested that the anticyclone in the Mongolia region might have developed the easterly wind, which transported warmer air from the east toward the LHG region and weakened the cold penetration of the westerlies, resulting in the temperature rise since the middle 1980s.

Despite the enormous applications of photosynthesis in global carbon budget and food security, photosynthesis research has not been adequately explored as a research focus in Nigeria. Previous works on C₃ and C₄ plants in Nigeria were mainly on the use of anatomical characteristics to delimit plant species into their respective pathways, with no attention being paid to its applications. In this review, past and present knowledge gaps in this area of study are elucidated. Information used in this review were sourced from referred research articles and books in reputable journals. The results revealed that C₃ and C₄ plants are distributed among 21 genera and 11 families in Nigeria. In addition there is dearth of informatio such that only three genera have been classified based on diverse photosynthetic pathways with no information found on the physiological and biochemical characterization of these genera. Moreover, further research is also suggested for tackling new challenges in the area of food productivity and climate change.

An analysis of the reasons for the displacements of long-term embankments maintained on permafrost soils indicates that they mainly occur due to plastic deformations in the layer of seasonal freezing and thawing; therefore, the reconstruction of permafrost is not effective in this case. It is proposed to strengthen these embankments with the help of using jet technology for cementation of the top layer of the roadbed. This approach is considered through the example of the deforming embankment on 6,278 km of the Turinskaya-Karymskaya section of the Trans-Siberian Railway.

Latitudinal permafrost in Northern Northeast (NNE) China is located in the southern margin of the Eurasian continent, and is very sensitive to climatic and environmental change. Numerical simulations indicate that air temperature in the permafrost regions of Northeast China has been on the rise since the 1950s, and will keep rising in the 21^st century, leading to extensive degradation of permafrost. Permafrost degradation in NNE China has its own characteristics, such as northward shifts in the shape of a "W" for the permafrost southern boundary (SLP), discontinuous permafrost degradation into island-like frozen soil, and gradually disappearing island permafrost. Permafrost degradation leads to deterioration of the ecological environment in cold regions. As a result, the belt of larch forests dominated by Larix gmelinii has shifted northwards and wetland areas with symbiotic relationships with permafrost have decreased significantly. With rapid retreat and thinning of permafrost and vegetation change, the CO₂ and CH₄ flux increases with mean air temperature from continuous to sporadic permafrost areas as a result of activity of methanogen enhancement, positively feeding back to climate warming. This paper reviews the features of permafrost degradation, the effects of permafrost degradation on wetland and forest ecosystem structure and function, and greenhouse gas emissions on latitudinal permafrost in NNE China. We also put forward critical questions about the aforementioned effects, including: (1) establish long-term permafrost observation systems to evaluate the distribution of permafrost and SLP change, in order to study the feedback of permafrost to climate change; (2) carry out research about the effects of permafrost degradation on the wetland ecosystem and the response of Xing'an larch to global change, and predict ecosystem dynamics in permafrost degradation based on long-term field observation; (3) focus intensively on the dynamics of greenhouse gas flux in permafrost degradation of Northeast China and the feedback of greenhouse gas emissions to climate change; (4) quantitative studies on the permafrost carbon feedback and vegetation carbon feedback due to permafrost change to climate multi-impact and estimate the balance of C in permafrost regions in the future.

Prediction on the coupled thermal-hydraulic fields of embankment and cutting slopes is essential to the assessment on evolution of melting zone and natural permafrost table, which is usually a key factor for permafrost embankment designin frozen ground regions. The prediction may be further complicated due to the inherent uncertainties of materialproperties. Hence, stochastic analyses should be conducted. Firstly, Karhunen-Loeve expansion is applied to attain the random fields for hydraulic and thermal conductions. Next, the mixed-form modified Richards equation for mass transfer (i.e., mass equation) and the heat transport equation for heat transient flow in a variably saturated frozen soil are combined into one equation with temperature unknown. Furthermore, the finite element formulation for the coupled thermal-hydraulic fields is derived. Based on the random fields, the stochastic finite element analyses on stability of embankment are carried out. Numerical results show that stochastic analyses of embankment stability may provide a more rational picture for the distribution of factors of safety (FOS), which is definitely useful forembankment design in frozen ground regions.

The interaction between the cryosphere and atmosphere is an essential and extremely sensitive mutual action process on the earth. Due to global warming and the cryospheric melting, more and more attention has been paid to the interaction process between the cryosphere and atmosphere, especially the feedback of the cryosphere change to the atmosphere. A comprehensive review of the studies on the interaction between the cryosphere and atmosphere is conducted from two aspects: (1) effects of climate change on the cryosphere or responses of the cryosphere to climate change; and (2) feedback of the cryosphere change to the climate. The response of the cryosphere to climate change is lagging. Such a lagging and cumulative effect of temperature rise within the cryosphere have resulted in a rapid change in the cryosphere in the 21st century, and its impacts have become more significant. The feedback from cryosphere change on the climate are omnifarious. Among them, the effects of sea ice loss and snow cover change, especially the Arctic sea ice loss and the Northern Hemisphere snow cover change, are the most prominent. The Arctic amplification (AA) associated with sea ice feedback is disturbing , and the feedback generated by the effect of temperature rise on snow properties in the Northern Hemisphere is also of great concern. There are growing evidence of the impact of the Arctic cryosphere melting on mid-latitude weather and climate. Weakened storm troughs, steered jet stream and amplified planetary waves associated with energy propagation become the key to explaining the links between Arctic cryosphere change and atmospheric circulation. There is still a great deal of uncertainty about how cryosphere change affects the weather and climate through different atmospheric circulation processes at different spatial and temporal scales due to observation and simulation problems.

A series of saline soil-related problems, including salt expansion and collapse, frost heave and thaw settlement, threaten the safety of the road traffic and the built infrastructure in cold regions. This article presents a comprehensive review of the physical and mechanical properties, salt migration mechanisms of saline soil in cold environment, and the countermeasures in practice. It is organized as follows: (1) The basic physical characteristics; (2) The strength criteria and constitutive models; (3) Water and salt migration characteristics and mechanisms; and (4) Countermeasures of frost heave and salt expansion. The review provides a holistic perspective for recent progress in the strength characteristics, mechanisms of frost heave and salt expansion, engineering countermeasures of saline soil in cold regions. Future research is proposed on issues such as the effects of salt erosion on concrete and salt corrosion of metal under the joint action of evaporation and freeze-thaw cycles.

Natural disasters inflict severe damage on almost the entire spectrum of social and natural habitats. This ranges from housing and shelter, water, food, health, sanitation to information and communication networks, supply of power and energy, transportation infrastructure, and others. Nepal is a risk prone country for Glacial Lake Outburst Flood (GLOF). GLOFs exist as major challenges as they repeatedly cause a heavy toll of life and property. During such a disaster, major challenges are indeed the protection of life, property and vital life-supporting infrastructure. Any delay or laxity in disaster relief can escalate the magnitude of distress for the victims. Thus, rather than trying to take curative measures, it is better to minimize the impacts of GLOF. These measures subsequently help in reducing the magnitude of death and casualties due to a GLOF event. This reduction of impact is often achieved by optimizing preventive measures. For applying necessary deterrent measures, it is essential to disseminate information about the danger beforehand. Early Warning System (EWS) is an important step for such information dissemination for GLOF disaster management and helps to anticipate the risk of disaster and disseminate information to lives at risk. It is impossible and impractical to reduce all GLOF risks, but it is possible to reduce several impacts of a GLOF through the implementation of the EWS. This paper presents the design and implementation of an EWS for monitoring potential outbursts of a glacier lake in the Dudh-Koshi Basin, Nepal.

This study was conducted to investigate the qualitative and quantitative phytochemical content of the crude extracts of Archidium ohioense, Pelekium gratum, and Hyophila involuta with different alcoholic solvents (ethanol, methanol, Seaman's Schnapps, fresh oil-palm wine, and fresh Raffia-palm wine). The mosses were collected from their natural populations on the central campus of the Obafemi Awolowo University, Ile-Ife, Nigeria. The yield of the extracts was weighed for all the solvents, and the qualitative and quantitative evaluations of the extracts were carried out using standard methods. The results of phytochemical analysis of the crude extracts from the mosses showed the presence of saponins, cardiac glycosides, triterpenes, alkaloids, flavonoids, and steroids. The quantitative phytochemical analysis of the crude extracts showed that ethanolic extracts of Hyophila involuta had the highest flavonoid content (288.37±0.10 mg RE/g), and Raffia-palm-wine extracts of Hyophila involuta had the highest saponin content (224.70±0.02 mg/g), while the methanolic extract of Archidium ohioense had the highest cardiac glycosides content (63.71±0.14 mg/g), and the Raffia-palm wine extract of Hyophila involuta had the highest alkaloids content (102.50±0.12 mg/g). Raffia- and oil-palm wines were observed to be the most effective solvents for all the mosses studied, followed by Seaman's Schnapp, while methanol and ethanol were less effective. The study concluded that the extracts of the mosses studied contain pharmacologically active constituents that can be used for therapeutic purposes.

Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western Tien Shan, Central Asia, was measured. We found that the average concentrations of black carbon was 2,180 ng/g, with a range from 250 ng/g to more than 10,000 ng/g. The average concentrations of organic carbon and mineral dust were 1,738 ng/g and 194 μg/g, respectively. Based on simulations performed with the Snow Ice Aerosol Radiative model simulations, black carbon and dust are responsible for approximately 64% and 9%, respectively, of the albedo reduction, and are associated with instantaneous radiative forcing of 323.18 W/m² (ranging from 142.16 to 619.25 W/m²) and 24.05 W/m² (ranging from 0.15 to 69.77 W/m²), respectively. For different scenarios, the albedo and radiative forcing effect of black carbon is considerably greater than that of dust. The estimated radiative forcing at Keqikaer Glacier is higher than most similar values estimated by previous studies on the Tibetan Plateau, perhaps as a result of black carbon enrichment by melt scavenging. Light-absorbing impurities deposited on Keqikaer Glacier appear to mainly originate from central Asia, Siberia, western China (including the Taklimakan Desert) and parts of South Asia in summer, and from the Middle East and Central Asia in winter. A footprint analysis indicates that a large fraction (>60%) of the black carbon contributions on Keqikaer Glacier comes from anthropogenic sources. These results provide a scientific basis for regional mitigation efforts to reduce black carbon.

In this study, a systematic survey of cultural airborne fungi was carried out in the occurrence environments of wall paintings that are preserved in the Tiantishan Grottoes and the Western Xia Museum, China. A bio-aerosol sampler was used for sampling in four seasons in 2016. Culture-dependent and -independent methods were taken to acquire airborne fungal concentration and purified strains; by the extraction of genomic DNA, amplification of fungal ITS rRNA gene region, sequencing, and phylogenetic analysis, thereafter the fungal community composition and distribution characteristics of different study sites were clarified. We disclosure the main environmental factors which may be responsible for dynamic changes of airborne fungi at the sampling sites. The concentration of cultural airborne fungi was in a range from 13 to 1,576 CFU/m³, no significant difference between the two sites at the Tiantishan Grottoes, with obvious characteristics of seasonal variation, in winter and spring were higher than in summer and autumn. Also, there was a significant difference in fungal concentration between the inside and outside of the Western Xia Museum, the outside of the museum was far more than the inside of the museum in the four seasons, particularly in the winter. Eight fungal genera were detected, including Cladosporium, Penicillium, Alternaria, and Filobasidium as the dominant groups. The airborne fungal community structures of the Tiantishan Grottoes show a distinct characteristic of seasonal variation and spatial distribution. Relative humidity, temperature and seasonal rainfall influence airborne fungal distribution. Some of the isolated strains have the potential to cause biodeterioration of ancient wall paintings. This study provides supporting information for the pre-warning conservation of cultural relics that are preserved at local sites and inside museums.

In semi-arid areas of China, gravel and sand mulch is a farming technique with a long history. In this study, a sample survey was conducted on long term gravel sand mulch observational fields in the Northwest Loess Plateau to determine the effects of long term mulch on soil microbial and soil enzyme activities. We found that after long term gravel-sand mulch, compared with bare ground, soil organic matter, alkali nitrogen, conductivity decreased, while pH and soil moisture increased. Urease, saccharase and catalase decreased with increased mulch thickness, while alkaline phosphatase was reversed. The results of Illumina MiSeq sequencing shows that after gravel-sand mulch, the bacterial and fungal community structure was different from bare land, and the diversity was reduced. Compared with bare land, the bacteria Proteobacteria and Acidobacteria abundance increased with increased thickness, and Actinobacteria was opposite. Also, at the fungal genus level, Fusarium abundance was significantly reduced, and Remersonia was significantly increased, compared with bare land. Redundancy analysis (RDA) revealed that soil environmental factors were important drivers of bacterial community changes. Overall, this study revealed some of the reasons for soil degradation after long term gravel-sand mulch. Therefore, it is recommended that the addition of exogenous soil nutrients after long term gravel-sand can help improve soil quality.

The building of railways on seasonally frozen ground is inevitable as China pursues economic development and the improvement of its citizens' living standards. However, railway construction in seasonally frozen soil areas is often faced with frost heave, leading to uneven subgrades which seriously threaten traffic safety. This article summarizes extant research results on frost heave mechanism, frost heave factors, and anti-frost measures of railway subgrades in seasonally frozen soil areas.

The Tibetan Plateau (TP) has powerful dynamics and thermal effects, which makes the interaction between its land and atmosphere significantly affect climate and environment in the regional or global area. By retrospecting the latest research progress in the simulation of land-surface processes (LSPs) over the past 20 years, this study discusses both the simulation ability of land-surface models (LSMs) and the modification of parameterization schemes from two perspectives, the models' applicability and improved parameterization schemes. Our review suggests that different LSMs can well capture the spatiotemporal variations of the physical quantities of LSPs; but none of them can be fully applied to the plateau, meaning that all need to be revised according to the characteristics specific to the TP. Avoiding the unstable iterative computation and determining the freeze?thaw critical temperature according to the thermodynamic equilibrium equation, the unreasonable freeze?thaw parameterization scheme can be improved. Due to the complex underlying surface of the TP, no parameterization scheme of roughness length can well simulate the various characteristics of the turbulent flux over the TP at different temporal scales. The uniform soil thermodynamic and hydraulic parameterization scheme is unreasonable when it is applied to the plateau, as a result of the strong soil heterogeneity. There is little research on the snow-cover process so far, and the improved scheme has no advantage over the original one due to the lack of some related physical processes. The constant interaction among subprocesses of LSPs makes the improvement of a multiparameterization scheme yield better simulation results. According to the review of existing research, adding high-quality observation stations, developing a parameterization scheme suitable for the special LSPs of the TP, and adjusting the model structures can be helpful to the simulation of LSPs on the TP.

Microbes inhabiting the desert respond sensitively to environmental changes and may be an indicator for changes in the desert ecosystem. Hypolithic microbial communities in the desert play a vital role in ecosystem processes such as soil formation and organic matter accumulation. This study investigated and compared the culturable bacterial community structure and diversity in hypolithic and peripheral soils, and the interaction between bacteria and environmental factors. The bacteria were isolated using four different kinds of media and identified by 16S rRNA gene-sequence analysis. The numbers of culturable bacteria in the hypolithic and peripheral soils ranged from 3.0×10⁴ to 3.6×10⁵ CFU/g and from 6.5×10⁴ to 5.3×10⁵ CFU/g, respectively, indicating that the bacteria number in peripheral soil was higher than that in hypolithic soil. A total of 98 species belonging to 34 genera were identified, among which Arthrobacter, Bacillus,and Streptomyces were found dominantly and widely distributed. The community of culturable bacteria had obvious sample specificity, and the diversity in hypolithic soil was higher than that in peripheral soil. On the regional scale, the distribution of culturable bacteria and the environmental factors showed regular changes. On the local scale, the high heterogeneity of the hypolithic environment determined the specificity of the number and species of culturable bacteria.

The Taklimakan Desert, the world's second largest desert, plays an important role in regional climate change. Previous studies on its spatial temperature features suffered from sparse conventional detection data, but the Atmospheric Infrared Sounder (AIRS) provides excellent temperature retrievals with high spatiotemporal resolution. Validation of AIRS temperature retrievals over desert regions with high land-surface emissivity, the key contributor to inversion error, is essential before using these data in regional weather/climate modeling. This paper examines the correlation coefficients, root mean square error (RMSE) and mean BIAS between AIRS-retrieved atmospheric temperature data and radiosonde observations (RAOBs) in the Taklimakan Desert hinterland and oases in the morning and at dusk. Firstly, the AIRS retrievals are consistent with RAOBs and are more consistent in the morning than at dusk. The consistency is better over a small-scale desert oasis than over a large-scale oasis in the morning and exhibits the opposite trend at dusk. The correlation coefficient over the hinterland is high in the morning but negative at dusk due to high desert-surface emissivity. Second, the RMSEs, which are all smaller than 3 K, are generally higher over desert sites than over oasis sites and slightly lower over a small-scale oasis than over a large-scale oasis in the morning. At dusk, the RMSEs are higher over desert sites than over oases and slightly higher over a small-scale oasis than over a large-scale oasis. Furthermore, the RMSEs are generally higher in the morning than at dusk over a large-scale oasis and lower in the morning than at dusk over a small-scale oasis. Third, the absolute mean BIAS values are mostly lower than 1 K. In the morning, relative to RAOB temperatures, the retrieval temperatures are higher over desert sites but lower over oasis sites. At dusk, the retrieval temperatures are lower than RAOB temperatures over both desert and oasis sites. The retrieval temperatures are higher than RAOB temperatures over desert sites in the morning but slightly lower at dusk. Most absolute mean BIAS values are higher in the morning than at dusk over both oasis and desert sites. Finally, the consistency between the AIRS and RAOB temperature data is high from 700 hPa to 100 hPa in the morning and from 700 hPa to 300 hPa at dusk. The difference between the AIRS and RAOB temperature data is generally higher in the morning than that at dusk. The RMSE differences between the AIRS and RAOB data are slightly lower in the morning than at dusk and are lower in the middle layers between 700 hPa and 150 hPa than in the layers above 150 hPa during both the morning and night. The BIAS is lower in the morning than at dusk below 300 hPa but higher in the upper layers. Moreover, the BIAS value is positive in the middle layers between 500 hPa and 150 hPa and negative at other levels at both times. Generally, the AIRS retrieval temperatures are reliable and can be used in further studies in the Taklimakan Desert.

This study investigated morphological variation and biomass accumulation that occurred in Sida acuta and Chromolaena odorata plants grown in lead polluted soil under organic fertilizer amendment. The study was carried out in the screen house at the Biological Gardens of the Obafemi Awolowo University, Ile-Ife, Osun State. The experiment was a factorial combination of one heavy metal (Pb) at five levels of concentration (0, 200, 400, 800 and 1,000 mg/kg) in a completely randomized design, and were replicated three times for each of the two plants and two levels (0 g/kg and 9.4 g/kg) of organic fertilizer (OBD-Plus). Each pot was filled with 5 kg of air-dried and sieved soil and placed on a plastic tray for the collection of excess water. Two weeks after planting, seedlings of uniform height were transplanted from the nursery to experimental pots at the rate of one seedling per pot and grown for 10 weeks. The growth parameters of the plants were biomonitored for 7 weeks. After 10 weeks of treatment, the plants were harvested and dried to calculate the biomass accumulation. The two plant species performed better under fertilizer application than without it. For each of the plant species the growth parameters decreased as the levels of Pb concentration increased. Furthermore, the plants' biomass decreased significantly (p<0.05) as the levels of Pb concentration increased. The organic fertilizer helped to improve the plants' performance in lead-polluted soil.

Fencing is the most common land-management practice to protect grassland degradation from livestock overgrazing on the Tibetan Plateau. However, it is unclear whether fencing reduces CO₂, CH₄, and N₂O emission. Here, we selected four vegetation types of alpine meadow (graminoid, shrub, forb, and sparse vegetation) to determine fencing effects on ecosystem respiration (Re), CH₄, and N₂O fluxes during the growing season. Despite increased average monthly ecosystem respiration (Re) for fenced graminoid vegetation at the end of the growing season, there was no significant difference between grazing and fencing across all vegetation types. Fencing significantly reduced average CH₄ uptake by about 50% in 2008 only for forb vegetation and increased average N₂O release for graminoid vegetation by 38% and 48% in 2008 and 2009, respectively. Temperature, moisture, total organic carbon, C/N, nitrate, ammonia, and/or bulk density of soil, as well as above- and belowground biomass, explained 19%~71% and 6%~33% of variation in daily and average Re and CH₄ fluxes across all vegetation types, while soil-bulk density explained 27% of variation in average N₂O fluxes. Stepwise regression showed that soil temperature and soil moisture controlled average Re, while soil moisture and bulk density controlled average CH₄ fluxes. These results indicate that abiotic factors control Re, CH₄, and N₂O fluxes; and grazing exclusion has little effect on reducing their emission—implying that climatic change rather than grazing may have a more important influence on the budgets of Re and CH₄ for the Tibetan alpine meadow during the growing season.

The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation (between October 2012 and January 2013), and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements—black pavement and insulation-black pavement—to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field conditions of the Changchun section (D3K692+840 to D3K692+860).The results show that: (1) Compared with cement pavement, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth; (2) the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3-1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4m and 0.7-0.8m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7-8 mm, which would meet the deformation limitestablished by the Code for Design on Special Subgrade of Railway; (3) the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximatelyfour months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and (4) compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggeststhat these two special pavements could provide better thermal stability for roadbeds.

Soil CO₂ efflux, the second largest flux in a forest carbon budget, plays an important role in global carbon cycling. Forest logging is expected to have large effects on soil CO₂ efflux and carbon sequestration in forest ecosystems. However, a comprehensive understanding of soil CO₂ efflux dynamics in response to forest logging remains elusive due to large variability in results obtained across individual studies. Here, we used a meta-analysis approach to synthesize the results of 77 individual field studies to determine the impacts of forest logging on soil CO₂ efflux. Our results reveal that forest logging significantly stimulated soil CO₂ efflux of the growing season by 5.02%. However, averaged across all studies, non-significant effect was detected following forest logging. The large variation among forest logging impacts was best explained by forest type, logging type, and time since logging. Soil CO₂ efflux in coniferous forests exhibited a significant increase (4.38%) due to forest logging, while mixed and hardwood forests showed no significant change. Logging type also had a significant effect on soil CO₂ efflux, with thinning increasing soil CO₂ efflux by 12.05%, while clear-cutting decreasing soil CO₂ efflux by 8.63%. The time since logging also had variable effects, with higher soil CO₂ efflux for 2 years after logging, and lower for 3-6 years after logging; when exceeded 6 years, soil CO₂ efflux increased. As significantly negative impacts of forest logging were detected on fine root biomass, the general positive effects on soil CO₂ efflux can be explained by the accelerated decomposition of organic matter as a result of elevated soil temperature and organic substrate quality. Our results demonstrate that forest logging had potentially negative effects on carbon sequestration in forest ecosystems.

The behavior and fates of environmental pollutants within the cryosphere and the associated environmental impacts are of increasing concerns in the context of global warming. The Tibetan Plateau (TP), also known as the "Third Pole", represents one of the most important cryospheric regions in the world. Mercury (Hg) is recognized as a global pollutant. Here, we summarize the current knowledge of Hg concentration levels, pools and spatio-temporal distribution in cryospheric environments (e.g., glacier, permafrost), and its transfer and potential cycle in the TP cryospheric region. Transboundary transport of anthropogenic Hg from the surrounding heavily-polluted regions, such as South and Southeast Asia, provides significant sources of atmospheric Hg depositions onto the TP cryosphere. We concluded that the melting of the cryosphere on the TP represents an increasing source of Hg and brings a risk to the TP environment. In addition, global warming acts as an important catalyst accelerating the release of legacy Hg from the melting cryosphere, adversely impacting ecosystems and biological health. Furthermore, we emphasize on the remaining gaps and proposed issues needed to be addressed in future work, including enhancing our knowledge on some key release pathways and the related environmental effects of Hg in the cryospheric region, integrated observation and consideration of Hg distribution, migration and cycle processes at a key region, and uses of Hg isotopic technical and Hg models to improve the understanding of Hg cycling in the TP cryospheric region.

Based on the engineering background of the contact channel between Shangyang and Gushan of Fuzhou Metro Line 2 undercrossing the existing tunnel line, the freezing temperature field of the contact channel, the displacement field of the existing tunnel line and the contact channel with different net distances and horizontal angles are analyzed by ANSYS finite element software and field measurement method. The obtained results indicate that during the freezing period, the temperature drops at different measuring holes are almost the same. The temperature near the bottom freezing tube drops faster than that far from the tube. It is found that the bilateral freezing technique improves the formation of the freezing wall in the intersection area. In this case, the intersection time of the cross-section is 7 days faster than that of the adjacent ordinary section. The change curve of the displacement of the surface uplift in different freezing periods with the distance from the center of the channel is "M" shaped. The maximum uplift displacement at 12 m from channel center is 25 mm. The vertical displacement of the measuring point located above the central axis of the connecting channel is large. The farther the point from the central axis, the smaller the corresponding vertical displacement. When the horizontal angle between the existing tunnel and the connecting channel is less than 60°, the existing vertical displacement of the tunnel changes rapidly with the horizontal angle, reaching 0.17 mm/°. Meanwhile, when the net distance is less than 6.1 m, the change rate of the vertical displacement of the tunnel is up to 2.4 mm/m.

Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly improve our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a classic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to inland areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been established on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quaternary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e.g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pollen extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened interdisciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification; secondly, laboratory experiments are needed to better constrain pollen transport dynamics in water and air; thirdly, more rigorous mathematical principles will improve the reliability of reconstructions and deepen the knowledge of plant geography; and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.

To explore the characteristics of plant calcium (Ca) fraction, we analyzed 91 plant species in the Ningxia Habahu National Nature Reserve in Yanchi County of Ningxia and 84 plant species in Zhenglan Banner of Inner Mongolia. Results show that, for the two regions, there is no significant difference between Ca fraction for the same growth type, and between water soluble Ca content or between hydrochloric acid soluble Ca content for plants of the same ecosystem and between hydrochloric acid soluble Ca content for plants of the same family. In similar vegetation zones, there is a significant difference among hydrochloric acid soluble Ca content for different growth types in Yanchi County and Zhenglan Banner, which was the highest for annual herbs and the lowest for perennial herbs. There is a significant difference between acetic acid soluble Ca content and between hydrochloric acid soluble Ca content for sandy land and grassland ecosystems in Yanchi County. There is a significant difference among the same Ca fraction of different families in the same region. Thus, the characteristics of plant Ca fraction are results of long-term adaptation to the environment.

Wedge-like structures filled with silty sand penetrate Quaternary fluvial and aeolian sediments and, in places, Tertiary bedrock on the Ordos Plateau, North China. The wedges reflect thermal contraction cracking of either permafrost or seasonal frost during the Late Pleistocene and early Holocene. Wedges of about 1 m in depth form polygonal nets of 2-3 m in diameter (type B). They contrast with wedges of 3-4 m in depth that form polygons of 10-15 m in diameter (type A). This review focuses upon the highly variable size of the inferred polygon nets and discusses the problem of differentiating between seasonally and perennially frozen ground, or between seasonal frost and permafrost.

Natural resource-management studies have become increasingly attentive to the influences of human factors. Among these, cultural biases shape people's responses to changes in natural resource systems. Several studies have applied grid-group cultural theory to assess the effects of multiple value biases among stakeholders on natural resource management. We developed and administered a questionnaire in the Heihe River Basin (n = 364) in northwestern China to investigate the appropriateness of applying this theory in the Chinese context of natural resource management. The results revealed various cultural biases among the respondents. In descending order of prevalence, these biases were hierarchism (46.98%), individualism (26.65%), egalitarianism (18.96%), and fatalism (2.78%), with the remaining respondents (4.67%) evidencing no obvious bias. Our empirical study revealed respondents' worldviews and the influence of sociodemographic characteristics on cultural biases, as theoretically posited. Among the variables examined, age had a positive and significant effect across all biases except individualism. The correlation of income to all cultural biases was consistently negative. Only education had a negative and significant effect across all biases. Women were found to adhere to egalitarianism, whereas men adhered to individualism and hierarchism. Thus, grid-group cultural theory was found to be appropriate in the Chinese context, with gender, age, education, and income evidently accounting for cultural biases. Relationships between environmental attitudes and cultural biases conformed with the hypothesis advanced by grid-group cultural theory. This finding may be of value in explaining individuals' environmental attitudes and facilitating the development and implementation of natural resource-management policies.