Characteristics and Classification of the Geothermal Gradient in the Beijing–Tianjin–Hebei Plain,China

Mathematical Geosciences - Study of the characteristics and classification of geothermal gradients can effectively guide the exploration and development of geothermal resources. In this paper, we...     

Spatial–temporal changes in meteorological and agricultural droughts in Northeast China: change patterns,response relationships and causes

Natural Hazards - Under the background of climate warming, drought events occur frequently. Generally, meteorological drought leads to agricultural drought. Understanding the spatiotemporal...     

Research on comprehensive carrying capacity of Beijing–Tianjin–Hebei region based on state-space method

Based on state-space method and component analysis, this paper builds a comprehensive evaluation system of carrying capacity for the Beijing–Tianjin–Hebei region from four aspects, namely economy, environment, ecology and energy. The results show that the comprehensive carrying capacity in this region gradually rises in recent years and the economic carrying capacity plays an important role in this situation. Ecological and environmental carrying capacity are gradually enhanced but still affected by water shortages. The energy carrying capacity of this region is low, which is the major factor restricting its sustainable development. Based on the empirical results, following policy suggestions should be adopted: Firstly, local government should accelerate technological progress, promoting the optimization and upgrading of industrial structure; Secondly, the contradiction between supply and demand of water resource should be solved gradually; thirdly, government should develop recycling economy, realizing the coordinated development of economy and environment; last but not least, saving energy and improving energy efficiency.     

Spatial and temporal variation of heavy metal contamination in sediments of Dexing region, Jiangxi Province, China

Mining is one of the most important contamination sources of heavy metals in sediments. Mining and mineral processing in the Dexing region of China have been carried out for over forty years. The aim of this study was to assess the spatial and temporal va…     

Spatial and temporal variation of precipitation during 1960–2015 in Northwestern China

Natural Hazards - Under the global climate change, research on the response characteristic of precipitation to climate change and its variation trend is of great significance. By employing the...     

Spatial–temporal characteristics of surface water quality in the Taihu Basin,China

Taihu Basin is one of the most developed and industrialized regions in China. In the last two decades, rapid development of economy as well as an increase in population has resulted in an increase of pollutants produced and discharged into rivers and lakes. Much more attention has been paid on the serious water pollution problems due to high frequency of algal blooming. The dataset, obtained during the period 2001–2002 from the Water Resources Protection Bureau of the Taihu Basin, consisted of eight physicochemical variables surveyed monthly at 22 sampling sites in the Taihu Basin, China. Principal component analysis (PCA) and cluster analysis (CA) were used to identify the characteristics of the surface water quality in the studied area. The temporal and spatial variations of water quality were also evaluated by using the fuzzy synthetic evaluation (FSE) method. PCA extracted the first two principal components (PCs), explaining 86.18% of the total variance of the raw data. Especially, PC1 (73.72%) had strong positive correlation with DO, and was negatively associated with COD_Mn, COD, BOD, NH₄ ⁺–N, TP and TN. PC2 (12.46%) was characterized by pH. CA showed that most sites were highly polluted by industrial and domestic wastewater which contributed significantly to PC1. The sites located in the west of Lake Taihu were influenced by farmland runoff which may contribute to nitrogen pollution of Lake Taihu, whereas the monitoring sites in the eastern of Lake Taihu demonstrated that urban residential subsistence and domestic wastewater are the major contaminants. FSE indicates that there is no obvious variance between 2001 and 2002 among most sites. Only several sites free from point-source pollution appear to exhibit good water quality through the studied period.     

Spatial and temporal distributions of mercury species and controlling factors in Hongfeng Reservoir, Guizhou, China

The Hongfeng Reservoir was built in 1960 and is an alkaline, hyper-eutrophic and seasonal anoxic reservoir due to the contamination from domestic and industrial wastewaters. The water samples at deferent depths from two sampling sites were collected from November 2003 to September 2004 using metal clean protocols. Total Hg （THg）, reactive Hg （RHg）, dissolved total Hg （DHg）, dissolved gaseous mercury （DGM） were measured by gold trap pre-concentration and CVAFS detection. Methyl mercury was measured by distillation followed by aqueous phase ethylation, precollection on a Tenax, isothermal gas chromatography and cold vapor atomic fluorescence detection. There was no discernible seasonal trend （about 8 ng/L） in THg concentration based on the average information developed during the four cruises except for high concentrations at bottom and water-sediment interface in May and September 2004. On the other hand, particulate mercury （PHg） and methyl mercury have discernible seasonal variability. Proportion of PHg increased from 29% in February 2004 to 50% in May 2004. In November 2003, February and May 2004 methyl mercury concentrations were relative low and increased with depth （from 0.13 to 0.40 ng/L）. In September 2004, methyl mercury concentrations increased from 0.14 ng/L in the epilimnion to 0.99 ng/L in the hypolimnion. DGM concentrations varied from 0.024 to 0.11 ng/L and decreased with depth.     

Spatial–temporal evolution of ore-forming fluids and related mineralization in the western Lanping basin,Yunnan Province,China

The Lanping basin is a significant Pb–Zn–Cu–Ag mineralization belt in the Sanjiang Tethyan metallogenic province. A series of sediment-hosted Himalayan Cu–Ag–Pb–Zn polymetallic deposits have been discovered in the western part of the basin, controlled by a thrust–nappe system. In the thrust–nappe system, the Cu orebodies mainly occur in the western and relatively deep part of the mineralization system (the root zone), whereas the Pb–Zn–Ag (± Cu) orebodies occur in the eastern and relatively shallow part of the system (the front zone), both as vein-type mineralization.In this paper we present new data, combined with existing data on fluid inclusions, isotopes and geologic characteristics of representative deposits, to provide the first study that contrasts mineralizing fluids in the Cu–Ag (Mo) and Pb–Zn–Ag (Cu) polymetallic deposits.Fluid inclusion and isotope studies show that the Cu–Ag (Mo) mineralization in the root zone formed predominantly from deep crustal fluids, with the participation of basinal brines. The deep crustal fluids are marked by high CO₂ content, relatively high temperatures (280 to 340 °C) and low salinities (1 to 4 wt.% NaCl equivalent), whereas the basinal brine shows relatively low temperatures (160 °C to 220 °C) and high salinities (12 to 22 wt.% NaCl equivalent), containing almost no CO₂. In comparison, hydrothermal activity associated with the Pb–Zn–Ag (± Cu) deposits in the front zone is characterized by basinal brine, with relatively low temperatures (130 °C to 180 °C), high salinities (9 to 24 wt.% NaCl equivalent), and low CO₂ concentrations. Although evolved meteoric waters have predominantly been proposed as the source for deep crustal fluids, magmatic and metamorphic components cannot be completely excluded. The basinal brine was predominantly derived from meteoric water.The δ³⁴S values of sulfides from the Cu–Ag (Mo) deposits and Pb–Zn–Ag (± Cu) deposits range from − 17.9 to 16.3‰ and from 2.5 to 11.2‰, respectively. These ranges may relate to variations in physicochemical conditions or compositional variation of the sources. Lead isotope compositions indicate that the ore-forming metals were predominantly derived from sedimentary rocks of the Lanping basin.     

Spatial–temporal variation of ecosystem service values in Ebinur Lake Wetland National Natural Reserve from 1972 to 2016, Xinjiang,arid region of China

National nature reserves in China protect ecosystem and well-being in its region while benefiting humans by providing ecosystem services. Land-use/cover changes result in changes in the landscape pattern and affect the provision of ecosystem service value (ESV). The monetary evaluation of spatial–temporal changes in landscape patterns and ecosystem services in the arid region of China has been inadequately studied. Therefore, the Ebinur Lake Wetland National Nature Reserve (ELWNNR) in the arid region of China was chosen as a study object to evaluate the spatial–temporal variation in ecosystem service values (ESVs) under changes in land use/cover. The research analysed land-use/cover change in ELWNNR using a Sankey diagram, the spatial–temporal variation in ELWNNR ESVs using ArcGIS. Meanwhile, it also analysed the landscape patterns and total ESVs of the core area, buffer area and experimental area of ELWNNR at a regional scale. Four Landsat data sets from 1972, 1998, 2007 and 2016 were chosen to estimate the changes in land-use/cover types and ESV in ELWNNR. Meanwhile, the sensitivity of ESV was also analysed to validate the estimation of ESV in ELWNNR. The results showed that the total ESV of ELWNNR was 3.12?×?10⁹ CNY (USD$ 4.88?×?10⁸) in 1972 and dropped to 2.71?×?10⁹ CNY (USD$ 4.24?×?10⁸) in 2016. The provision of total ESV in ELWNNR decreased by approximately 0.41?×?10⁹ CNY (USD$ 6.42?×?10⁷) from 1972 to 2016, although there were fluctuations in 1998 and 2007. The core area possessed the highest ESV among all the areas, showing an increase in the provision of ESV in ELWNNR. All the areas of ELWNNR became highly fragmented, and the landscape patterns became more complex during this time period. The results of the study provide sufficient information about the ecosystem services in the region in the absence of complete data sets and contribute to conservation planning of national nature reserves.     

Temporal analysis of air pollution and its relationship with meteorological parameters in Bahrain, 2006–2012

The objective of this paper is to analyze temporal and seasonal trends of air pollution in Bahrain between 2006 and 2012 by utilizing datasets from five air quality monitoring stations. The non-parametric and robust Theil-Sen approach is employed to study quantitatively temporal variations of particulate matter (PM₁₀ and PM_2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃). The calculated annual concentrations for PM₁₀ and PM_2.5 in Bahrain were substantially higher than recommended World Health Organization (WHO) guideline standards. Results showed increasing trends for PM₁₀, PM_2.5, and SO₂ whereas O₃ and its precursor NO₂ showed decreasing behavior. The general increase in air pollution trends is in agreement with prediction of air pollution models for Middle East region due to economic growth, industrialization, and urbanization. The significances of long-term trends were examined. Additional to actual (unadjusted) trends, meteorological adjusted (deseasonalized) trends and seasonal trends were quantified. The box-plot analysis visually illustrated monthly variations of key air pollutants. It showed that only PM₁₀ and PM_2.5 exhibited seasonal pattern, and their concentrations increased during summer and decreased during winter. The effects of ambient air temperature, relative humidity, wind speed, and rainfall on particulate matter (PM) concentrations were further investigated. The Spearman correlation coefficient results demonstrated significant negative correlation between relative humidity and PM concentrations (??0.595 for PM₁₀ and ??0.526 for PM_2.5) while significant positive correlation was observed between temperature and PM concentrations (0.420 for PM₁₀ and 0.482 for PM_2.5).     

Hydrogeochemistry and Origin of Thermal Groundwater in Bedrock Aquifers in Tianjin, China

INTRODUCTIONThermalgroundwaterisfoundtohaveoccurredinthebedrockcarbonateaquifersofLowerPaleozoicandMeso toNeo ProterozoicErathemsnearTianjin ,China .Thebedrockaquifersexistinthelayersbetweenabout 10 0 0mandmorethan 4 0 0 0mbelowthelandsurface .Thethermalwaterhasbeensuccessfullydevelopedoverthepast2 0yearstoprovideasourceofhotwaterforavarietyofresidentialandindustri alpurposes.Geothermalwellstappingtheaquifersarecapa bleofproducingcommercialquantitiesofhotwaterwiththetemperaturesranging…     

Spatial and temporal distribution of polycyclic aromatic hydrocarbons in finegrained sediments of the East China Sea

The nearshore mud area along the Changjiang （Yangtze River） estuary and the coast of Zhejiang and Fujian provinces, and the distal mud area to the southeast of Cheju Island, Korea are the modem accumulative centers, thus, being the ＂sinks＂ of pollutants such as Polycyclic Aromatic Hydrocarbons （PAHs） in the East China Sea （ECS）. PAHs of surface sediment samples from the mud areas of the ECS and a ^210Pb dating sediment core collected using a gravity core from the coastal mud area in the ECS were quantified by GC/MSD with the internal standard materials.     

Radon in “nonradonic” ground waters of the Baikal region: Spatial and temporal variations

Based on the analysis of radon concentrations in several dozen springs and wells, three groups were distinguished for the waters classified as “nonradonic.” The spatial regularities of the distribution of these groups were revealed, along with the quantitative characteristic of the anomalies and the background, in view of their belonging to the Baikal and Transbaikal hydromineral provinces of the region.     

Spatial and temporal distribution of polycyclic aromatic hydrocarbons in fine- grained sediments of the East China Sea

The nearshore mud area along the Changjiang (Yangtze River) estuary and the coast of Zhejiang and Fujian provinces, and the distal mud area to the southeast of Cheju Island, Korea are the modern accumulative centers, thus, being the “sinks” of pollutant…     

Understanding regional development mechanisms in Greater Beijing Area,China, 1995–2001, from a spatial–temporal perspective

Due to its rapid economic gains in recent decades, studies of China’s regional development have recently attracted scholarly attentions. Multi-scalar and multi-mechanism are proposed as crucial approaches in China’s regional studies. More advanced methodological development in GIS and spatial analysis also lends power to in-depth understanding of China’s regional development. This study examines the development mechanisms from a spatial–temporal perspective in Greater Beijing Area (GBA), China. In particular, with panel data of GBA from 1995 to 2001 at county level, the study intends to apply a spatial panel regression analysis to study the well identified regional development mechanisms, namely, institutional factors, globalization and urbanization. Based on the panel data analysis, a tentative geographically and temporally weighted regression (GTWR) is also proposed to explore the potentially varying relationships between economic development and its mechanisms from a space–time standpoint. Results from the analyses are quite interesting. First, when urbanization seems to hinder regional development in GBA with cross-sectional analysis, the spatial panel analysis indicates that urbanization contributes to GBA’s development in the 7 years span. Second, per capita foreign investment, which was usually deemed one of the major factors of globalization and a financial engine for regional development in the reform China, turns out to be a negligible mechanism in GBA’s development. Third, among all the development mechanisms, the government’s financial capability seems to dominate the regional development in GBA. GTWR analysis further revealed potential non-stationary relationships among the modeled variables, indicating that the functions of regional development mechanisms are inherently heterogeneous both spatially and temporally in GBA.