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Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jinci Spring is one of the most famous karst spring in Northern China and is the main drinking and irrigation water source of Taiyuan city, Shanxi Province. It has special significance in terms of humanities and water resources. Because of the continuous over-exploitation of groundwater, the water level of groundwater has been decreased significantly. The flow of Jinci Spring has decreased year by year since the 1970s, and in 1994 it cut off completely. The flow cutoff has brought huge losses to the local economy and negatively impacted the ecological environment. From the hydrogeological conditions of Jinci Spring area to study, the dynamic change in karst groundwater level will provide a basis for the protection and rational exploitation of karst water in the spring area. The previous research on Jinci Spring area was limited to the spring flow and water level changes, lack of analysis to the overall spring area and the decay process of spring flow. This paper takes the overall spring area as research object. According to groundwater level data over 1961–2012, the period is divided into two phases of decline and recovery. Human activities in the region and corresponding groundwater evolution at various stages were systematically analyzed, and the reservoir capacity was calculated for each period of decline. The results show that the average reservoir capacity decreased from 920 (1954–1960) to 116 (1961–1977) to 31 (1978–1994) million m3. The important effect of "Water Resumption" project on groundwater in the area during the remediation period was also analyzed. In the light of observed increases in groundwater level during this stage, the project has a notably positive effect. [ABSTRACT FROM AUTHOR]

Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on observations and historical simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) archive, the contributions of human activities (including greenhouse gases (GHGs), anthropogenic aerosols (AAs), and land use (LU)) and external natural forcings (Nat) to climate changes in China over the past 50 years were quantified. Both anthropogenic and external natural forcings account for 95%-99% of the observed temperature change from 1951-1975 to 1981-2005. In particular, the temperature changes induced by GHGs are approximately 2-3 times stronger than the observed changes, and AAs impose a significant cooling effect. The total external forcings can explain 65%-78% of the observed precipitation changes over the past 50 years, in which AAs and GHGs are the primary external forcings leading to the precipitation changes; in particular, AAs dominate the main spatial features of precipitation changes in eastern China. Human activities also dominate the long-term non-linear trends in observed temperature during the past several decades, and, in particular, GHGs, the primary warming contributor, have produced significant warming since the 1960s. Compared to the long-term non-linear trends in observed precipitation, GHGs have largely caused the wetting changes in the arid-semiarid region since the 1970s, whereas AAs have led to the drying changes in the humid-semihumid region; both LU and Nat can impose certain impacts on the long-term non-linear trends in precipitation. Using the optimal fingerprinting detection approach, the effects of human activities on the temperature changes can be detected and attributed in China, and the effect of GHGs can be clearly detected from the observations in humid-semihumid areas. However, the anthropogenic effects cannot be detected in the observed precipitation changes, which may be due to the uncertainties in the model simulations and to other issues. Although some results in this paper still need improvement due to uncertainties in the coupled models, this study is expected to provide the background and scientific basis for climate changes to conduct vulnerability and risk assessments of the ecological systems and water resources in the arid-semiarid region of China. [ABSTRACT FROM AUTHOR]

Subalpine meadows in the Dongling Mountains (located at E115º26′-115º40′, N40º00′-40º05′) of Beijing, China are important for tourism and the provision of ecosystem services. However, because of poor management serious degradation has occurred on these subalpine meadows. The aim of this paper is to present a quantitative analysis of effects of tourism disturbance and topography on the status and diversity of montane meadow communities and to provide direction for improved management. Sixty quadrats of 2 × 2 m along 10 transects were set up to collect data on site characteristics and vegetation status. The relationships between community composition and structure, species diversity, and tourism disturbance and topographic variables were analyzed by multivariate methods (TWINSPAN and CCA). The results showed that eight meadow communities were identified by TWINSPAN. Most of them were seriously degraded. The first CCA axis identified an elevation and tourism disturbance intensity gradient, which illustrated that tourism disturbance and elevation were most important factors influencing meadow types, composition and structure. Some resistant species and response species to tourism disturbance were identified and can be used as indicator species of tourism disturbance. Species richness, heterogeneity and evenness were closely related to tourism disturbance and elevation. It is concluded that tourism disturbance must be controlled to enable grassland rehabilitation to occur in the meadows. Measures of effective management of the meadows were discussed. [ABSTRACT FROM AUTHOR]

The swing of the main channel of the Qiantang River is controlled by the high-water and low-water changes in the river, as well as the impact of large-scale reclamation of tidal flats. Its evolution in modern times is the result of the combined functions of natural and man-made factors. This paper analyzes the cause of the formation of the South Channel and Xisan Tidal Furrow and proposes the regulation principle of “To regulate the river and reclaim tidal flats by taking the advantage of local topography”. It is suggested to cut off the South Channel and Xisan Tidal Furrow completely to restrict the swing of the main channel and to increase the reclamation area of the tidal flat at the same time. [ABSTRACT FROM AUTHOR]

Long-duration extreme cold events in China were often characterized by strong simultaneous high-pressure anomalies (SHA) over the Ural and the North Pacific regions, e.g., 2018. It is unclear how human activity and the SHA influenced the long-duration extreme cold events in China, respectively. Herein, we investigated variations in such long-duration cold events during the past 60 years and contributions of human activity and the related atmospheric circulation pattern. Results show since 2008, the coldest periods in each winter in eastern China have become colder than those in the 1980s and 1990s, which caused an enlarging temperature difference between China and the Northern Hemisphere. We found that an increase in SHA resulted in the cold events colder and longer than a single high anomaly, through a combined reinforcing effect on the high-latitude ridges and a blocking effect on eastward movement of the East Asian trough. The UHA dominates the intensity of cold events, while the PHA modulates the duration of cold air. Comparative analysis indicated that, the enhanced SHA offsets part of the anthropogenic warming effect, resulting in extreme cold events still occurring in warm winters. And strong SHA can increase the probability of the strong cold events to about twice that with weak SHA. It is meaningful to deeply understand variations of cold events under global warming. [ABSTRACT FROM AUTHOR]

Nitrogen pollution of groundwater is becoming more and more serious due to intense and extensive industrial and agricultural activities. This may exert great influence on human health. In this paper, human health risk due to groundwater nitrogen pollution in Jinghui canal irrigation area in Shaanxi Province of China where agricultural activities are intense was assessed. Forty-seven groundwater samples were collected from shallow wells and analyzed for physicochemical indices in the study area. Water samples were analyzed for pH, total dissolved solids (TDS), total hardness (TH), major ions (Na+, K+, Ca2+, Mg2+, HCO3−, CO32−, Cl− and SO42−), nitrate (NO3-N), nitrite (NO2-N) and ammonia nitrogen (NH4-N). General groundwater chemistry was described by statistical analysis and the Piper diagram. Water quality was quantified via comprehensive water quality index (CWQI), and human health risk was assessed considering the age and exposure pathways of the consumers. The results show that the shallow groundwater is slightly alkaline and groundwater types are HCO3·SO4·Cl-Mg and HCO3·SO4·Cl-Na. Rock weathering and evaporation are main natural processes regulating the groundwater chemistry. The CWQI indicates that groundwater in the study area is seriously polluted by TH, TDS, SO42−, Cl− and NO3−. Human health risk is high because of high concentrations of nitrate in drinking water. The results also show that children are at higher risk than adults. The health risk through dermal contact is much lower than that through drinking water intake and can be ignored. [ABSTRACT FROM AUTHOR]

Purpose: Soil erosion and sediment transport are often induced by a few extreme precipitation events. Currently, there is limited information on the effects of changes in precipitation extremes on river sediment load over a long time period at the basin scale. The objectives of this study were to quantify the effects of variations in precipitation extremes on sediment load in the Second Songhua River Basin (SSRB), northeast China. Materials and methods: Daily precipitation data from 10 meteorological stations within the SSRB and sediment load data during 1960–2014 from the basin outlet hydrological station were collected. Six extreme precipitation indices, such as erosive precipitation (ERPTOT), wet-day precipitation (PRCPTOT), very wet day precipitation (R95pTOT), flood season precipitation (FSPTOT), maximum 1-day precipitation (RX1day) and heavy precipitation (HP), were used to detect the precipitation extremes. The Mann–Kendall non-parametric trend analysis was used to analyze the dynamic changes in precipitation extremes and sediment load. The double cumulative curve method was used to assess the effects of changes in precipitation extremes on sediment load. Results and discussion: The results indicated that six extreme precipitation indices showed periodic variations from 1960 to 2014, while they did not show any significant change trend in the SSRB (p > 0.05); however, the sediment load showed an extremely significant decreasing trend (p < 0.01) over the past 55 years. Sediment load significantly correlated with six precipitation extremes indices (p < 0.05). Compared with the baseline period (1960–1977), the sediment load was reduced by 1.12 × 106 ton per year (1977–2014). The contribution of precipitation extremes to the sediment load ranged from -22.83% to 6.97%. The corresponding contribution of the non-precipitation factor to sediment load was from 93.03% to 122.83%. Conclusions: The change in precipitation extremes was not the main reason for the sediment load reduction. Sediment load reduction in the SSRB was due to the interactions between multiple factors. Non-precipitation factors, such as reservoir construction, were the main reasons for the sediment load reduction. These findings are useful to understand the variation of river sediment load and to adopt countermeasures to relieve potential risk of precipitation extremes. [ABSTRACT FROM AUTHOR]

Rapid economic development in coastal areas has gradually increased the risk of coastal water quality deterioration. The assessment methods of coastal water quality are multifarious, but many depend on either subjective judgment or objective calculation. We proposed a weighted sum methodology by integrating the subjective analytic hierarchy process and objective entropy theory (AHP-entropy weight methodology) to obtain an overall evaluation of coastal water quality. The mathematical models to transform the biochemical and physical parameter values and soluble substance concentrations into index scores have been formulated in comparison to the national water quality classification scheme. The application of the AHP-entropy weight methodology was demonstrated in the nearshore area of Yangjiang city, China, based on 23 seawater sampling stations in autumn 2017 and spring 2018. Datasets including biochemical and physical parameters, nutrients, and heavy metals have been converted into water quality index scores based on the proposed mathematical model. Results revealed that the overall water quality fell into the "good" class in both sampling seasons. The spatial distribution of the water quality index scores demonstrated that the relatively worse water quality occurred in estuarine and nearshore areas, signifying the negative effect of coastal anthropogenic activities. The statistical analyses like the hierarchical cluster analysis interpreted that the river input acted as a main source of pollutants in the study area. The AHP-entropy weight methodology could be a preferred way to assist decision-makers in properly evaluating the current state of coastal water quality in an unbiased, objective manner. [ABSTRACT FROM AUTHOR]

The history and mechanisms of dust storms in northern China remain unclear owing to the paucity of reliable long-term, high-resolution geological records. In this study, we reconstructed the dust storm history of the last ~500 years in northern China, based on sedimentary coarse fraction (>63 µm) of a well-dated core from Lake Daihai, Inner Mongolia. The high-resolution data reveal three intervals of frequent dust storms: AD 1520–1580, AD 1610–1720, and AD 1870–2000. The dust storm events in the Lake Daihai area were broadly synchronous with those inferred from other historical or geological records and generally occurred during cold intervals. Changes in the intensity of Siberian High and the westerlies modulated by temperature variations are the likely major factors controlling dust storm dynamics. An interesting feature is that although the intensities of dust storms have been systematically increased during the recent warming period, a clear decreasing trend within this period is evident. The recent increase in average dust storm intensity may be ascribed to an increase in particle supply resulting from a rapid increase in human activity, whereas the weakening trend was likely caused by decreases in average wind speed resulting from the recent global warming. [ABSTRACT FROM AUTHOR]

Evaluating anthropogenic impacts on regional vegetation changes during historical time is not only important for a better understanding of the Anthropocene but also valuable in improving the vegetation-climate models. In this study, we analyzed stable isotopes (δ18O, δ13C) and trace elements (Mg/Ca, Sr/Ca) of a stalagmite from Huangchao Cave in central Shandong, northern China. 230Th and AMS14C dating results indicate the stalagmite deposited during 174BC and AD1810, with a hiatus between AD638 and 1102. Broad similarities of the δ18O and trace elements in the stalagmite suggest they are reliable precipitation indexes. The δ13C of the stalagmite, a proxy of vegetation change, was generally consistent with local precipitation and temperature variations on a centennial-scale before the 15th century. It typically varied from −9.6‰ to −6.3‰, indicating climate controlled C3 type vegetation during this period. However, a persistent and marked increasing trend in the δ13C record was observed since the 15th century, resulting in δ13C values from −7.7‰ to −1.6‰ in the next four centuries. This unprecedented δ13C change caused by vegetation deterioration cannot be explained by climate change but is fairly consistent with the dramatically increasing population and farmland in Shandong. We suggest that the increasing deforestation and reclamation in central Shandong began to affect vegetation in the mountain region of central Shandong since the 15th century and severely destroyed or even cleared the forest during the 16th–18th century. [ABSTRACT FROM AUTHOR]

Continued long-term monitoring of vegetation activity in national key ecological function zones (NKEFZs) has implications for national ecological security and sustainability in China. We used Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) dataset to map and analyze the spatiotemporal patterns of change in vegetation growth and their linkage with climate change and human activities in NKEFZs during 1982–2013. Statistically significant increases of growing season, spring, and autumn NDVI were observed during all or most periods while 25 NKEFZs are taken as a whole. Non-significant decreases of NDVI were found in 7 NKEFZs during a few periods, and obvious increases were observed during fifteen periods in all other NKEFZs. Vegetation growth in NKEFZs was mainly regulated by a thermal factor, and the dominant climatic drivers varied across different regions and seasons. The influence of temperature was stronger on vegetation activity in spring and autumn for those NKEFZs located in high latitudes and high elevations, while precipitation was the main climatic control factor for NKEFZs in the arid and semi-arid regions. The effects of human activity on the NDVI of NKEFZs were not ignored; a significant decrease of NDVI in the Sanjiang Plain may be related to the rapid change in land use from wetland into farmland. [ABSTRACT FROM AUTHOR]

This study examines the spatiotemporal evolution of China's flash flood disasters (FFDs) since 1949 and explores driving factors affecting the spatial distribution of historical FFDs. Records of more than 60000 FFDs are examined, and the centroid comparison method is used to reveal the spatiotemporal evolution of FFDs from 1951 to 2015. In particular, the geographical locations of the centroids, degrees of aggregation, and associated movement tendencies are examined to conduct a preliminary analysis of correlations between rainfall, population, and the spatiotemporal evolution of FFDs. Subsequently, using relevant data from 2000 to 2015, three factors relating to FFDs in natural watershed units include namely rainfall, human activity, and the environment of the Earth's surface. The geographical detector method is then employed to explore the effect of these driving factors on the spatial distribution of FFDs. Analysis results show that displacement of the spatial distribution of FFDs since 1949 is correlated with variations in rainfall and population distribution. In addition, it is determined that the distribution of FFDs occurring between 2000 and 2015 have regional differentiation characteristics. However, the effect of rainfall on the distribution of FFDs is more significant than that of human activity or the environment of the Earth's surface, but interactions occur between these latter two factors in disaster-formative environments. Furthermore, results also show that the driving factors of FFDs have significant spatiotemporal heterogeneity. In China, regions at high risk of FFDs include the Sichuan-Chongqing ecological zone, the South China ecological zone, the Yunnan-Guizhou Plateau, and the middle and lower reaches of the Yangtze River, while regions with a low risk of FFDs include the Northwest China arid zone, Qinghai-Tibet Plateau, Inner Mongolian Plateau, and the Northeast China ecological zone. These findings support further studies investigating disaster-formative environments, facilitate FFD risk zoning, and provide a scientific basis for plans to effectively prevent and control FFDs. [ABSTRACT FROM AUTHOR]

Context: The world's largest dam-the Three Gorges Dam (TGD)-has been in operation for more than 10 years. While the recent shrinkage of large lakes and increased severe droughts in the downstream have been subjectively ascribed to TGD, empirical support based on thorough analysis is still lacking, leaving a gap for ecologists to quantify the TGD impacts on the surrounding landscapes. Objectives: This study aims to quantify the impacts of TGD water impoundment on downstream landscapes in terms of lake shrinkage and severe droughts. Methods: We have incorporated the recent findings and conducted a comprehensive analysis based on long-term datasets and contrasting scenarios with and without the presence of TGD. The datasets were constructed from hydrological measurements, a hydrodynamic model, and satellite data retrieval techniques. Results: Here we show that, in addition to natural variations due to climatic conditions, TGD water impoundment has indeed weakened river's ability in preventing backflows from its connected lakes directly contributed to their shrinkage. The impoundment substantially increased the intensity and severity of droughts downstream, and may have produced a cluster of impacts on the changing landscape. Conclusions: Our finding provides needed information for assessing TGD's impacts on environmental services in the region, and raises serious concerns with the ongoing large-scale hydraulic project-China's South-to-North Water Transfer Project-which will further reduce the flow of the Yangtze River. [ABSTRACT FROM AUTHOR]

Understanding the relationship between surface water and groundwater is important for the integrated management of water resources in arid regions. In the present study, the connectivity of river water and shallow groundwater along the Shidi River, China is estimated using a connectivity index, as well as analyses of hydrochemistry and isotopic signature. The three approaches for hydraulic connectivity assessment were compared and discussed. An end member mixing analysis was performed to estimate the contribution ratios of local precipitation, river leakage and groundwater lateral inflow to the total groundwater recharge along the river. The results show that medium connectivity is identified in all reaches of the river (upstream, midstream and downstream). Water table depth and river channel sediments are the major factors responsible for the spatial variation of the hydraulic connectivity. The CI approach can be adopted to generate preliminary assessment results of hydraulic connectivity, while the physiochemical and isotopic approaches should be used as a tool for results validation and verification. Groundwater lateral inflow is the most important recharge source of groundwater along the river, while river leakage only accounts for 18.4-27.0 % of the total recharge. This study is meaningful in integrated water resources management in arid regions and the methods used in this study can be adopted by other scholars in similar studies. [ABSTRACT FROM AUTHOR]

China's water source includes the headwaters of the Yangtze, Yellow, and Lantsang (the Mekong outside China) rivers and is located in the heart of the Tibet Plateau, which has an average altitude of 4,200 m. Due to the importance of the Water Tower to the ecological security and economic development of China and South Asia, desertification issues in this region have attracted the attention of the public, scholars, government officials, and international organizations. Combined satellite-derived vegetation indices, field surveys, and surface meteorological data to evaluate the effects of climate change, our analyzed results show that during the early part of the twenty-first century, no desertification occurred in these source areas. However, between 2000 and 2010, human activities may have had a negative effect on about 50 % of the region, although vegetation rehabilitation still occurred during this period. Although the Ecological Protection and Restoration Program was launched in China in 2005, the negative impacts of human activities such as agriculture have still increased in the water source. Vegetation rehabilitation in these source areas appears to be driven mainly by the effect of climate change, and it is possible that human activities do not play an important role in regional ecological and environmental evolution. Although at present we cannot determine whether it was rising temperatures or increasing precipitation that enhanced vegetation growth in the region, our results show that the dominant factors controlling vegetation rehabilitation in China's Water Tower are related to climate. [ABSTRACT FROM AUTHOR]

Lacustrine sediments can provide potential information about environmental changes in the past. On the basis of high-resolution multi-proxy analysis including carbon and nitrogen contents of organic matter, C/N ratios, inorganic carbon contents, and carbon and oxygen isotopic composition of carbonate, together with precise Cs dating, the environmental evolution of Lake Chenghai, Yunnan Province, during the past 100 years has been investigated. It is shown that the carbonate in Lake Chenghai is authigenic, and the organic matter is mainly derived from aquatic plants and algae, instead of terrestrial-source materials. The environmental evolution of Lake Chenghai can be diverged into three periods with the contrasting characteristics during the past 100 years. Before 1940, the stable carbon and oxygen isotope values, the poor correlation between them and the lower carbon and nitrogen contents of organic matter suggested that Lake Chenghai was open, and the lake water was oligotrophic during that period. During 1940-1993, the negative δC values and the gradual increase of carbon and nitrogen contents of organic matter and C/N ratios indicated that the eutrophication was aggravated. The closeness of Lake Chenghai and human activities may be responsible for this eutrophication. After 1993, notable increases in carbon and oxygen isotopic values of carbonate, carbon and nitrogen contents of organic matter, C/N ratios and inorganic carbon contents demonstrated that the increase of lacustrine productivity and the serious eutrophication were resulted from strong human activities. Therefore, the multi-proxy in Lake Chenghai sediments has reliably recorded the natural environmental evolution and the impacts from human activities. [ABSTRACT FROM AUTHOR]

Environmental degradation of wetlands is a major issue in the Yellow River Delta of China. Natural threats and human activities, such as flow cut-off of the Yellow River and droughts, population growth and urbanization, cause wetlands degradation of the delta during the last century, especially in the recent 50 years. Wetland degradation in the Yellow River Delta was investigated and its causation was analyzed. The results indicated that landscape changes of wetlands were mostly tremendous in the whole delta, namely loss of wetland area, surface water and groundwater pollution. Some new degradation control measures based on traditional and scientific knowledge must be used to reverse the wetlands degradation in the Yellow River Delta. [ABSTRACT FROM AUTHOR]

The Minqin Basin is at the lower reach of the Shiyang River of Gansu province in northwest China. Dramatic decline in groundwater level has resulted from over-abstraction of groundwater since the late 1950s to satisfy increasing irrigation and other demands. Severe water shortage led to environmental degradation. To better understand the spatial-temporal variation of groundwater levels and to evaluate the groundwater resources in the region, a three-dimensional regional groundwater flow model was built and calibrated under transient condition. The MODFLOW program was used and the research area was discretized as a square network with cell size of 400 × 400 m. The model showed that the aquifer was under destructive stress, with a groundwater resource deficit of 260 million cubic meters per year (Mm/year) on average. Since the inflow of surface water from the upstream basin has declined to about 100-150 Mm/year in recent decades, the irrigation return flow had become the main recharge and accounted for 60.6% of total recharge; meanwhile, abstraction by pumping wells took 99.2% from the total groundwater discharge. [ABSTRACT FROM AUTHOR]

With activities that alter the structure and function of the habitat, humans have a direct impact on ecosystems and ecosystem services, i.e., the conditions and processes that sustain human life. In this study, 35 townships in the Yanhe watershed in the Loess Plateau of China were selected. The net primary production (NPP), carbon sequestration and oxygen production (CSOP), water conservation, and soil conservation were the ecosystem services selected and valuated. Human activity was quantified by an integrated human activity index (HAI) based on population density, farmland ratio, and the influence of road networks and residential areas. The NPP, CSOP, and water conservation showed a conspicuous spatial pattern fanning outward from the southwest, while the soil conservation showed an obscure spatial pattern distinguished primarily by the peripheral area surrounding the urbanized areas. Total ecosystem services in the Yanhe watershed demonstrated a decreasing pattern from south to north, and the HAI was in proportion to administrative and economic development. Based on the selected ecosystem services and HAI, we mapped the townships of the Yanhe watershed by cluster analysis, and provided sustainable ecosystem management suggestions, tailored to the social-ecological map. [ABSTRACT FROM AUTHOR]

The Songhua River plays a key role in the national development of China, owing to its unique natural condition and resources. Recent changes in the streamflow in the Songhua River are important with regard to local sustainable development and management under the background of global warming and aggravating soil erosion. In order to detect changes in the streamflow, two streamflow series from 1955 to 2004 (observed at the Harbin and Jiamusi stations) in the mainstream of Songhua River basin were obtained, and methods of statistical analysis, wavelet transform, and double mass analysis were employed to analyze the data. Reasons for the changes to the streamflow are discussed with respect to natural and man-made drivers. The results show the following: (1) From 1955 to 2004, the streamflow series present obvious declining trends. (2) The streamflow series followed the pattern of a wet-dry-wet-dry cycle pattern over the past 50 years. In the mainstream of Songhua River, wet years mainly occurred during the periods of 1955-1966 and 1984-1993, while dry years mainly occurred in the 1970s and after 2000. (3) Within the 50-year scale, the streamflow series appeared in the main periods of circa 33-, 13- and 4-year, in which the 33-year periodicity is the strongest. (4) Precipitation and temperature directly influenced the streamflow in the mainstream of the basin. The discharge was positively correlated with the precipitation and negatively correlated with the temperature. In addition, human activity was another important driving factor for streamflow change. (5) In the mainstream of Songhua River basin, the influences on streamflow can be divided into three periods: 1955-1976, 1977-1997, and 1998-2004. In the first period climate change played a dominant role, and during the latter two periods human influences were enhanced significantly. [ABSTRACT FROM AUTHOR]

Global surface temperature shows an increasing trend over the past 100 years. Anthropogenic and natural factors have been invoked to explain this warming, but their relative contribution and the spatial variability remain controversial. Based on a 2650-year temperature record from a stalagmite near Beijing, we explore the possible impacts of human activity on the warm season temperature in Beijing since the industrial era using the method of singular spectrum analysis (SSA). The results suggest that the warm season temperature in Beijing under the natural forcing should have an overall decreasing trend for the past 130 years (1870 to 2000 AD) with an amplitude of 0.45±0.84°C, while the instrumental record and stalagmite data show an increase of 1.08°C. These imply that human activity would have caused an increase in the warm season temperature of Beijing for about 1.53±0.84°C compared to its natural trends, from 1870 AD to 2000 AD. Our results also suggest that anthropogenic forcing began to significantly influence the temperature since 1870 AD, and the effect further intensified since 1915 AD. [ABSTRACT FROM AUTHOR]

The Minqin Oasis and its adjacent regions in northern China experienced significant desertification beginning 2,000 years ago and continuing to the present, and numerous studies have claimed that human activities, especially the flourishing of agriculture, have played a major role in environmental change in this region. Our analysis suggests that the observed desertification was mainly controlled by changes in the water component of the ecosystem and the arid climate. The impacts of cultivation on desertification from 2,000 years ago to the mid-1900s appear to have been relatively minor compared to the impacts of the area’s arid climate and its native geomorphological processes. Although human activity has increased from the late-1940s to the present, and the areas of the oasis reclaimed for agriculture have reached a maximum, desertification over the past 50 years appears to be a continuing process that began thousands of years ago, and is mainly controlled by decreasing water levels caused by the arid climate, local geomorphological processes and overuse of water in the upstream. Although both human activities and climate variation are important drivers of the desertification process, and it is not possible to completely separate the human influence from the climate impact, key factors on controlling desertification should be investigated before we place the blame solely on the flourishing of agriculture in this region. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

We review published stratigraphic, archaeological and pedosedimentary evidence in order to reconstruct the history of soil erosion in China. Documentary evidence of climatic and flood events of the Yellow River and modern hydrological and meteorological data are synthesised to analyse the history of past human activity and its effects on soil erosion intensity during four nested periods of time during the Quaternary. The most intensive period of erosion during the Quaternary was in the Holocene. During the Holocene, intervals of intensive soil erosion occurred at 7500–7000 BP, 200 BCE–0 CE, 1000–1600 CE (Christian era) and during the 1930s, 1950s and the later part of the 1960s of the last century. Large-scale human activity including warfare during early Chinese history, population migration, the inner wars in 1930s, the Cultural Revolution and the recent national campaign to aid soil and water conservation are all closely related to the rate of soil erosion on the Loess Plateau and to sediment loads in the Yellow River. Overall, soil erosion during the transition from dry-cool to wet-warm climates was more intense than during wet-warm and cool-dry climatic episodes, but serious accelerated soil erosion has occurred during the last 2,500 years because of man-induced devastation of vegetation and other anthropogenic disturbance of the environment. Modern rates of soil erosion on the Loess Plateau are a combination of both intensive natural and human-induced erosions and are some four times greater than occurred in the geological past. The recent implementation of soil and water conservation measures has decreased sediment load in the Yellow River by 25%. [ABSTRACT FROM AUTHOR]

Water environmental degradation is a major issue in the Heihe River Basin belonging to the inland river basin of temperate arid zone in northwestern China. Mankind’s activities, such as dense population and heavy dependence on irrigated agriculture, place immense pressure on available and limited water resources during the last century, especially the recent five decades. An investigation on the water environmental degradation in the Heihe River Basin and analysis of its causation were conducted. The results indicated that water environmental changes in the whole basin were tremendous mostly in the middle reaches, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Some new forms of management based on traditional and scientific knowledge must be introduced to solve problems of water environmental degradation in the Heihe River Basin. [ABSTRACT FROM AUTHOR]

Core and surface sediment samples were collected from three sub-lakes (Lake Nanyang, Lake Dushan and Lake Zhaoyang) in the Uke Nansi Basin, Shandong Province. In order to reveal the characteristics of spatial and historical distribution of heavy metals in different sublakes of the Upper Lake Nansi, heavy metal (As, Cr, Cu, Hg, K. Mn, Ni, Pb, Zn, AI, Fe, Ti and V) concentrations of sediment samples were investigated. Based on the activity of 137Cs in the sediments, the modem accumulation rate of Lake Nansi sediments is 3.5 mm/a. Our results show that the whole Upper Lake Nansi has been already polluted by heavy metals, among which Lake Nanyang has been polluted seriously by mercury, as well as by lead and arsenic, while lake Dushan has been most seriously polluted by lead and arsenic. Historical variation of heavy metal (Cr, Cu, K, Ni, Zn, Al, Fe, Ti and V) concentrations shows an abrupt shift in 1962, resulting in a division of two periods: from 1957 to 1962 when metal enrichment increased with time, and from 1962 to 2000 when it decreased with time, while that of some anthropogenic elements such as Hg, Pb and Mn tend to increase toward the surface. However, the variation trend of As in the sediments is different from that of Hg, Pb and Mn, with its maximum value appearing in 1982. Since 1982 the concentrations of As have decreased due to the forbidden use of arsenite pesticides. This variation trend revealed changes in manner of human activity (coal combustion, waste discharges from both industries and urban sewage) within the catchment during different periods. [ABSTRACT FROM AUTHOR]