Area Of Northwest China Research Articles

Characteristics of meteorological drought pattern and risk analysis for maize production in Xinjiang, Northwest China

Xinjiang is an important maize cultivation area in Northwest China. Investigating the relationship between meteorological drought and climate-driven maize yield can help to mitigate the negative impacts of drought on agricultural production in Xinjiang. In this study, multi-source data, including meteorological, agricultural, and socio-economic data, are collected to analyze the spatiotemporal patterns of drought and assess drought disaster risk. The standardized precipitation evapotranspiration index is calculated to classify different drought grades in the study area. The main results are as follows: (1) the relationship between drought and climate-driven maize yield is determined using a stepwise regression analysis, which indicates that drought conditions occurring from May to July are crucial for the yield in Xinjiang; (2) the modified Mann-Kendall test detects that the frequency-intensity-coverage of drought from May to July shows a decreasing tendency as a whole in the study area; (3) the correlation analysis shows that the multivariate ENSO index may be the dominant force in regional drought evolution; and (4) a drought disaster risk assessment system is constructed based on principles of natural disaster management. The drought disaster risk is higher in southwestern and northwestern Xinjiang, areas that should deserve more attention.

Temporal and spatial variations of the thermal growing season in China during 1961–2015

ABSTRACTBased on the daily mean air temperature at 1863 meteorological stations over China from 1961 to 2015, the temporal and spatial tendencies in the growing season parameters (the start date of the growing season, GSS; the end date of the growing season, GSE; and the length of the growing season, GSL) for 0, 3, 5 and 10 °C temperature thresholds were investigated; the results showed that in the past 55 years GSL exhibited a significant extending trend at speeds of 1.5–5.0 days per 10 years in most areas of northwest China (NWC), north China (NC), northeast China (NEC) and western southwest China (SWC). The extension of GSL was attributed to an earlier GSS at a rate of 1.5–3.0 days per 10 years in most areas of NEC and NC and some parts of NWC and SWC, and a later GSE at speeds of 1.0–2.0 days per 10 years in most of NWC and northern SWC and some parts of NEC and northwestern NC. The extending trend of the GSL was prominent in northern and western China relative to southern China. The temporal variations in the regional average growing season parameters were different for four temperature thresholds and in six regions. In general, the regional GSL (GSS, GSE) was extended (advanced, delayed) continuously during 1961–2015 or had no significant trend before about 1980 and then extended (advanced, delayed) continuously. The temporal variations of the GSE were weaker than those of the GSS in most regions.

Hydrochemical and Stable Isotope (δD and δ18O) Characteristics of Groundwater and Hydrogeochemical Processes in the Ningtiaota Coalfield, Northwest China

Understanding the sources and mechanisms of groundwater recharge in the Ningtiaota Coalfield, an arid area in northwest China, is important for water resources management and coal mine safety. Hydrochemical and stable hydrogen and oxygen isotopic data were used to study water–rock interactions and groundwater recharge in the area. A total of 45 water samples, including surface water, Quaternary groundwater, and Jurassic Zhiluo Group (J2z) and Yan’an Group (J2y) groundwater, were collected for major ions and stable isotope (δD and δ18O) analyses. Our results showed that the groundwater originated from atmospheric precipitation, and experienced weak evaporation during infiltration. Water in the study area has a low salinity and is dominated by HCO3–Ca type. The dominant water–rock interactions in the Jurassic Zhiluo Group (J2z) groundwater were dissolution of silicate minerals, gypsum, and halite and cation exchange. The results may aid in water resources management and groundwater inrush prevention in the coalfield and at other coal mines.

Assess the Impact of Climate Change on Water Resources in the Xi’an Heihe River Basin

Climate change is a complex problem and becoming the leading challenge for humankind in the 21st century. Therefore, assessing climate change impacts on the social, economic activities and proposed solutions to respond to climate change is urgent and necessary. The Soil and Water Assessment Tool (SWAT) model provides an efficient way to assess complex water resources management problems of a watershed. In this research, we used the SWAT model to evaluate the impact of potential climate change on the availability of water resources in the Heihe River Basin, which supplies major drinking water to over three million people in Xi’an City, China. The response of the hydrologic system in this basin to climate change must be analyzed to provide a scientific foundation for planning future water managements, including groundwater diversions, dealing with adverse effects of more intensive floods and severe droughts, and reservoir water protection in the Heihe River Basin. To our knowledge, this is the first attempt to combine SWAT model with GCM outputs for urban water resources area in northwest China to assess the effects of climate change on river runoff. For this purpose, the SWAT model was first calibrated and then validated using the monthly streamflow data during the period of 2005~2009 and 2010~2013, respectively, from the Heihe River. Based on the calibrated model, the future water resources of the Heihe River Basin under the climate change scenario of the A1B from the IPCC report was simulated. The predicted annual runoff in the Heihe River Basin in the next 40 years (from 2020) shows an increase after a reduction, with the change in the average annual runoff ratio of -11.0%, -6.4%, 7.2%, and 190% for each of the next four consecutive decades. The average runoff during the flood season reaches a maximum in the 2050s, which may lead to serious challenges in flood control in the middle and lower reaches of the Heihe River region.

Effects of Cd on Uptake of P in Potato Grown in Sierozems

ABSTRACTThe effects of Cd on the bioaccumulation of P in soil-plant system have aroused wide interest and been widely explored. Sierozem has been contaminated by Cd in many areas in Northwest China. To investigate the effects of Cd on the uptake and translocation of P in plants in sierozem, pot experiments were carried out by cultivating potato (Solanum tuberosum L.) under Cd treatment. The fractions of Cd in the soil were examined by soil extraction; available P in the soil was determined; Cd and P accumulation in the plants was also determined. The result of the soil extraction shows that the acid-soluble Cd fraction gradually became the main fraction with the increasing Cd concentrations in the soil. This suggests that the change in the main fraction of Cd may promote the uptake of Cd in plants because acid-soluble Cd fraction may be utilized easily by plants. Given increasing Cd concentrations in the soil, Cd concentrations increased in each part of potato plants, whereas the soil available P and plant P contents were decreased. These results indicate that increasing Cd concentrations in sierozems exerts negative effects on the uptake and translocation of P in plants.

3-D wavelet-based fusion approach for comprehensively analyzing multiple physical-property voxel models inverted from potential-field data

The fusion technique is a simple and fast but useful tool for integrated interpretation of various types of geophysical data. Based on the routine 2-D wavelet-based image fusion approach, we presented a 3-D wavelet-based fusion approach for comprehensively analyzing various physical-property voxel models inverted from gravity and magnetic data. The approach decomposes the models via the 3-D discrete wavelet transformation, and then fuses them according to the separated fusion rules of the approximated and detailed components in the wavelet domain, and then reconstructs the fused model via the inverse 3-D discrete wavelet transformation. The related parameters of the approach include the wavelet basis, the layer number of decomposition, the weighted coefficients for fusing the approximated components, and the window size for fusing the detailed components. Tests on the synthetic data and the real data from a metallic deposit area in Northwest China verified feasibility of the 3-D fusion approach.

Distributions and ecological risk assessment of estrogens and bisphenol A in an arid and semiarid area in northwest China.

Free estrogens (estrone, E1; 17β-estradiol, 17β-E2; estriol, E3; and 17α-ethinylestradiol, EE2), their corresponding sulfate and glucuronide conjugates, and bisphenol A (BPA) were investigated in water and sediments in the Fen River catchment, an arid and semiarid area in northwest China. E1 and BPA were frequently detected in the wet and dry sampling seasons. In addition to the sulfate conjugates, other conjugated estrogens were not detected in water and sediments. The concentrations of these compounds in water generally increased from upstream to downstream. The concentrations in water samples of most sites were higher in the wet season than those in the dry season, but concentrations in sediments of most sites were higher in the dry season than those in the wet season. The distributions of these compounds in sediments were positively correlated with the total organic carbon (TOC) contents of sediments (0.3<R 2<0.6, p<0.01) and concentrations in water (0.25<R 2<0.50, p<0.01). In this catchment, E1 was the main contributor to endocrine disrupting risk. The surface water in most of the tributaries and the sewage in the drainage channels were at risk. The pore waters of sediments were at risk at most sampling sites.

Evaluation of ecological effectiveness of protected areas in Northwest China

Protected areas (PAs) have experienced explosive growth in Northwest China over the last three decades, but their effectiveness in representing regional ecological system diversity has not attracted considerable attention. Low effectiveness would exacerbate the conservation-development conflicts, particularly those that arise as a result of the Great Western Development Strategy (GWDS). Thus, an assessment of the effectiveness of the PA network has become quite important. We proposed natural vegetation communities to represent regional ecological system diversities, and proposed Global 200 Priority Ecoregions, Important Bird Areas, and ecosystem function regions to represent important conservation areas. To determine their effectiveness, we studied the extent to which ecological system diversities and important conservation areas are represented by the existing 96 PAs. Our results indicated that the total coverage of vegetation communities in PAs in Northwest China is not sufficiently comprehensive. As the PA system has expanded, the growth in the total area of the PAs has been greater than that of their vegetation community richness. While most of the important conservation areas are covered by PAs, some regions have not yet reached the 10% threshold; further, PAs are distributed unevenly and conservation gaps remain in the region. Therefore, these regions should receive more attention when planning new PAs. It is vital that more biodiversity datasets and assessment of ecosystem function regions are integrated in order to provide a basis for the government to formulate appropriate protection and development strategies.

The assessment of Hantaan virus-specific antibody responses after the immunization program for hemorrhagic fever with renal syndrome in northwest China

ABSTRACT Xianyang city is one of the main hemorrhagic fever with renal syndrome (HFRS) epidemic areas in northwest China. Although the HFRS immunity program has been provided in this city, HFRS is still occurred every year. In order to implement the vaccination program effectively and to control HFRS, the analysis of antibody responses specific to Hantaan virus (HTNV) in individuals after vaccination is essential. In this study, a total of 100 subjects were divided into 5 groups: unvaccinated, 1, 3, 29 and 33 months after boost vaccination. The levels and the positive rates of HTNV-NP-specific IgM and IgG antibodies as well as HTNV neutralizing antibodies were significantly increased in the serum of the vaccinated individuals. The positive rates and levels of HTNV-NP-specific IgG and HTNV neutralizing antibody reached their highest values at 3 months respectively and could be sustained up to 33 months after vaccination. Moreover, the titres of HTNV-NP-specific IgM or IgG antibody and the titres of HTNV neutralizing antibody at 1 month after vaccination have a positive correlation. The level of HTNV-NP-specific IgG antibody was much higher than that of HTNV-NP-specific IgM antibody or HTNV neutralizing antibody. In addition, the strongest responses of antibody-secreting cells were observed at 3 months after vaccination, which was consistent with the serum results. Therefore, the HFRS immunization program is effective to induce humoral immunity in the population of northwest China.

Effects of Heavy Metals from Soil and Dust Source on DNA Damage of the Leymus chinensis Leaves in Coal-Mining Area in Northwest China.

Air and soil pollution from mining activities has been considered as a critical issue to the health of living organisms. However, few efforts have been made in distinguishing the main pathway of organism genetic damage by heavy metals related to mining activities. Therefore, we investigated the genetic damage of Leymus chinensis leaf cells, the air particulate matter (PM) contents, and concentrations of the main heavy metals (Pb, Cd, Cr, Hg) in soil and foliar dust samples collected from seven experiment points at the core mining area and one control point 20 kilometers away from the core mining area in Inner Mongolia in 2013. Comet assay was used to test the genetic damage of the Leymus chinensis leaf cells; the Tail DNA% and Tail Moment were used to characterize the genetic damage degree of the plant cells. The comet assay results showed that the cell genetic damage ratio was up to 77.0% in experiment points but was only 35.0% in control point. The control point also had the slight Tail DNA% and Tail Moment values than other experiment groups. The cell damage degree of the control group was 0.935 and experiment groups were 1.299–1.815. The geo-accumulation index and comperehensive pollution index(CPI) were used to characterize heavy metal pollution in foliar dust samples, and single factor pollution index and CPI were used to characterize the heavy metal pollution in soil samples. The CPIfoliar dust of control group was 0.36 and experiment groups were 1.45–2.57; the CPIsoil of control group was 0.04 and experiment groups were 0.07–0.12. The results of correlation analyze showed that Air Quality Index (AQI) -CPIfoliar dust(r = 0.955**)>Damage degree-CPIfoliar dust(r = 0.923**)>Damage degree-AQI(r = 0.908**)>Damage degree-CPIsoil (r = 0.824*). The present research proved that mining activity had a high level of positive correlation with organism genetic damage caused by heavy metals through comparing with the control point; soil and atmosphere were both the important action pathway for heavy metal induced genetic damage in mining area. Furthermore, heavy metal contents in foliar dust showed a higher positive correlation with genetic damage than when compared with soil. This means the heavy metal contents that L.chinensis absorbed through respiration from the atmosphere could make more serious genetic damage than when absorbed by root systems from soil in the mining area. This study can provide theoretical support for research on plant genetic damage mechanisms and exposure pathways induced by environmental pollution.

A hybrid Bayesian network approach for trade-offs between environmental flows and agricultural water using dynamic discretization

Abstract Agriculture and the eco-environment are increasingly competing for water. The extension of intensive farmland for ensuring food security has resulted in excessive water exploitation by agriculture. Consequently, this has led to a lack of water supply in natural ecosystems. This paper proposes a trade-off framework to coordinate the water-use conflict between agriculture and the eco-environment, based on economic compensation for irrigation stakeholders. A hybrid Bayesian network (HBN) is developed to implement the framework, including: (a) agricultural water shortage assessments after meeting environmental flows; (b) water-use tradeoff analysis between agricultural irrigation and environmental flows using the HBN; and (c) quantification of the agricultural economic compensation for different irrigation stakeholders. The constructed HBN is computed by dynamic discretization, which is a more robust and accurate propagation algorithm than general static discretization. A case study of the Qira oasis area in Northwest China demonstrates that the water trade-off based on economic compensation depends on the available water supply and environmental flows at different levels. Agricultural irrigation water extracted for grain crops should be preferentially guaranteed to ensure food security, in spite of higher economic compensation in other cash crops’ irrigation for water coordination. Updating water-saving engineering and adopting drip irrigation technology in agricultural facilities after satisfying environmental flows would greatly relieve agricultural water shortage and save the economic compensation for different irrigation stakeholders. The approach in this study can be easily applied in water-stressed areas worldwide for dealing with water competition.

Association between vitamin D receptor gene FokI polymorphism and skeletal fluorosis of the brick-tea type fluorosis: a cross sectional, case control study

BackgroundBrick-tea type fluorosis is a public health concern in the north west area of China. The vitamin D receptor (VDR)-FokI polymorphism is considered to be a regulator of bone metabolism...

Impact of Irrigation Methods on Soil Salt Content and Their Differences in Whole Cotton Growing Season in Arid Area of Northwest China

Abstract: Research for changes of soil water and salt is an important content of land sciences and agriculture sciences in arid and semi arid regions. In this paper, sampling in actual agricultural fields, laboratory analysis of soil samples and statistical analysis methods are used to quantitatively analyze soil salinity changes under different irrigation methods throughout the cotton growing season in Shihezi reclamation area. The results show that irrigation methods play an important role in soil salt content in the surface soil (0–20 cm) and sub-deep soil (40–60 cm), followed by deep soil layer (60–100 cm) and root soil layer (20–40 cm). Furrow irrigation yields the maximum soil salt content in deep layer (60–100 cm) or sub-deep layer (40–60 cm) and the maximum salinity occurs in the first half of the cotton growing season (June or earlier). In contrast, drip irrigation yields the maximum soil salinity in the root layer (20–40 cm) or sub-deep (40–60 cm), and this usually appears in the second half gro...

Quantitative Analysis of Groundwater Recharge in an Arid Area, Northwest China

The Mixing Cell Model (MCM) is a useful tool that can be applied to areas with limited hydrogeological data, such as arid areas in northwest China, to transform available groundwater hydrochemical data into quantitative information about an aquifer. In this study, we used the MCM to quantify water circulation in the study area and to analyze information such as the supply source composition and proportion of the confined aquifer, the main supply aquifer for local drinking water. The MCM simulation results showed that the confined aquifer in the study area is mainly recharged by leakage of water from the upper unconfined aquifer and lateral flow from the eastern and southern tablelands. Unconfined groundwater and lateral flow contributed to 67.69% and 32.31% of the recharge, respectively. The groundwater circulation model of the study area provided quantitative information about water circulation in different parts of the study area, represented by different cells known as A–F. The information from this model provides a scientific basis for the sustainable use and development of water resources in different parts of the study area.

Current Status of the Research on Coal Geology in China

AbstractCoal is the main energy in China, which has already played and will continue to play an important role in the national economy. Coal geology, as a practical science, has an access to gradual development with the growth and prosperity of China. From the meaning of the coalfield geology, this paper introduces the research progress and status of coalfield geology, including the research on coal basin, stratigraphy of coal‐bearing stratigraphie sequences, coal‐forming process, structural geology of coalfields, and exploration and development status of coal resources. The paper specially focuses on coal‐forming process, including coal formation in terrestrial facies and transgressive / regression events, and introduces new technology which has been applied to research progress in structural geology of coalfield. This paper puts forward a new comprehensive exploration system for coal exploration and reviews regional coal geological exploration results in recent years, such as coal‐poor regions of seven provinces in southern China and the coal resources area in northwest China, which will be an important coal‐producing area in the future.

Detecting changes in future precipitation extremes over eight river basins in China using RegCM4 downscaling

AbstractTo detect the frequency and intensity of precipitation extremes in China for the middle 21st century, simulations were conducted with the regional climate model RegCM4 forced by the global climate model GFDL_ESM2M under the middle emission scenario (RCP4.5). Compared with observed precipitation extremes for the reference period from 1982 to 2001, RegCM4 generally performed better in most river basins of China relative to GFDL. In the future period 2032–2051, more wet extremes will occur relative to the present period in most study areas, especially in southeast China while significantly less dry extremes will occur in arid and semiarid areas in northwest China. In contrast, areas in northwest China showed an increase in the trend of dry extremes (CDD) and a decrease in the trend of wet extremes (R95p and Rx5day), which might result in more drought in the future. Finally, we discuss in detail the possible reason of these processes, such as zonal wind, vertical wind, and water vapor. In the Huaihe river basin (HU), reduced south winds in summer (June–August) and a decrease of the upward vertical p velocity cause less future precipitation and might lead to changes of extreme events. We also completed correlation analysis between the precipitation extreme indices and the climate factors and found that the precipitation extremes were more sensitive to the annual and seasonal mean precipitation, total water vapor, and upward vertical wind relative to the geopotential height and 2 m temperature over most river basins in China. Perhaps the changes of some wet extremes could be verified partly through changes of annual precipitation due to their high consistence.

Ecological Functions of PV Power Plants in the Desert and Gobi

Abstract: Photovoltaic (PV) power generation is an emerging energy industry that is developing rapidly. A number of PV power plants have been established in the desert and Gobi areas in northwest China in recent years. Is there any ecological significance to the establishment of PV power plants? If yes, what is it? This paper tries to find the answer by analyzing meteorological data from the Hexi Corridor as well as the observational data of light and vegetation in the Minqin desert area. The results show that the solar energy converted from 1 m2 of PV panels is equivalent to the solar energy that is utilized by 260.75 m2 of desert plants in the desert area. In China, there is vast area of desert and Gobi, with frequent dust storms and aeolian sand, as well as rich sunlight resources. Therefore, to develop the PV industry in the desert and Gobi regions will not only create considerable economic benefits, but will also be of great ecological significance. On the one hand, PV can effectively regulate thermo...

Household concentrations and personal exposure of PM2.5 among urban residents using different cooking fuels

Exposure to PM2.5 is a leading environmental risk factor for many diseases and premature deaths, arousing growing public concerns. In this study, indoor and outdoor PM2.5 concentrations were investigated during the heating and non-heating seasons in an urban area in northwest China. Personal inhalation exposure levels among different age groups were evaluated, and the difference attributable to different cooking fuels including coal, gas and electricity, was discussed. The average concentrations of PM2.5 in the kitchen and the bedroom were 125±51 and 119±64μg/m3 during the heating season, and 80±67 and 80±50μg/m3 during the non-heating season, respectively. Indoor PM2.5, from indoor combustion sources but also outdoor penetration, contributed to about 75% of the total PM2.5 exposure. Much higher indoor concentrations and inhalation exposure levels were found in households using coal for cooking compared to those using gas and electricity. Changing from coal to gas or electricity for cooking could result in a reduction of PM2.5 in the kitchen by 40–70% and consequently lower inhalation exposure levels, especially for children and women.

Simulation of Water Use Dynamics by Salix Bush in a Semiarid Shallow Groundwater Area of the Chinese Erdos Plateau

This study analyzed the water use of the Salix psammophila bush in a semi-arid area in northwest China using a Hydrus-1D model. The model incorporated the effect of thermally driven water flow coupling liquid water, water vapor and heat transport. The model was calibrated and validated using hourly field measurements of soil water content and temperature at different depths for a growing season of 154 days. Furthermore, another Hydrus-1D model was established to simulate environments with decreased heat, rainfall or temperature and an increased leaf area index using calibrated and validated parameters. Our results show that upward and downward thermally driven water vapor fluxes account for 0.11% and 0.28%, respectively, of the corresponding direction of total water flux during the bush’s growing season. Although the vapor flux is very small, simulations incorporating heat flow revealed alterations in the temperature and pressure head gradients over the root zone, especially during dry periods. Consequently, the cumulative contributions of groundwater to evapotranspiration (ETg) with heat flow and without heat flow were 26.9% and 40.6%, respectively, during the simulation period. Therefore, the cumulative contribution of groundwater to ETg is overestimated when heat flow is excluded. Thus, we recommended that heat transport be incorporated when evaluating ETg in arid and semi-arid areas.

Digital Elevation Data Fusion Using Multiple-Point Geostatistical Simulation

This paper proposes advanced methods based on multiple-point geostatistical simulations (MPSs) for data fusion in digital elevation models (DEMs). MPS-based methods can capture similar patterns using the spatial correlation residing in the training images and then reproduce the area of interest in terms of spatial patterning through conditional simulation. For this, the FILTERSIM algorithm, which is based on MPS, can be applied to augment the prediction results from traditional geostatistical approaches to derive fused datasets from complementary sources. However, the FILTERSIM algorithm discerns similar patterns based on a filter-based prototyping process and does not account for nonstationarity of spatial structures. Thus, an enhanced data fusion method based on a modified FILTERSIM algorithm was proposed, in which new strategies for forming prototypes were incorporated. An experiment was carried out in a study area in Northwest China to test the proposed methods. The aim is to produce fused DEM datasets at fine spatial resolution by integrating fine-resolution but sparsely sampled SRTM data and regularly gridded coarse-resolution GMTED2010 data, and then to test three data fusion methods: 1) the traditional geostatistical interpolation, which provides baseline results for comparison; 2) the conventional FILTERSIM algorithm; and 3) a modified FILTERSIM algorithm. For both the first and second methods, three different kriging approaches were used; for the third method, three new schemes for building prototypes were tested for an improvement in performance. The results show that the improved FILTERSIM method can achieve greater accuracy and retain more spatial structure than the other two methods.