Table of Content

    20 July 2018, Volume 33 Issue 7 Previous Issue    Next Issue
    Resource Economics
    Inspection, Measurement and Interpretation of Club Convergence of Water Resources Utilization Efficiency in China: 2003-2015
    ZHOU Di, ZHOU Feng-nian
    2018, 33 (7):  1103-1115.  doi: 10.31497/zrzyxb.20170638
    Abstract ( )   HTML ( )   PDF (754KB) ( )   Save
    The study of club convergence of water resources utilization efficiency will help the government carry out regional water resource management more targetedly and focus on areas that have long been “trapped” in low efficiency. The paper studied the phenomenon of club convergence of total water use efficiency, agricultural water use efficiency and industrial water use efficiency in the 31 provinces of the mainland of China during 2003-2015 using extended Markov chain and extended spatial Markov chain model based on the Quah (1997) distribution dynamics analysis framework. Firstly, we examined the club convergence of three types of water efficiency. Then, we measured the extents of club convergence based on the constructed club convergence index. Finally, the phenomena of three types of club convergence were explained from a spatial point of view. The results show that: 1) There are a phenomenon of club convergence in the three types of water use efficiency which will be eased with time, but the phenomenon is still evident. For example, the probability that area with low industrial water use efficiency remained low after five years is 0.808, while that high-level remained high after five years is 0.918. Therefore, the coordination of regional water resources efficiency needs to be strengthened. 2) The industrial water use efficiency is the highest in the degree of club convergence, followed by the total water use efficiency, and the agricultural water efficiency is the lowest. The degree of differential curing of industrial water use efficiency is the most serious one that some areas have remained at low level for a long time and are caught in a “low level trap”, which should be taken seriously by the government. 3) The phenomenon of club convergence is influenced by spatial factors. On one hand, the adjacent areas with different water use efficiency have a certain influence on the water use efficiency in a region that high level adjacent areas have positive impact and low level adjacent areas have negative impact. On the other hand, there are spatial agglomerations of high and low level clubs, so there is spatial spillover effect inside clubs. However, the positive spillover effect in high level clubs is much larger than that in low level clubs, which makes the difference between high and low level clubs widen further so as to promote the phenomenon of club convergence. This is particularly evident in the club convergence of industrial water use efficiency in China.
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    Assessing the Compensation Standard of Water-saving Irrigation Technology from the Perspective of External Benefits: Based on Choice Experiment
    XU Tao, ZHAO Min-juan, QIAO Dan, SHI Heng-tong
    2018, 33 (7):  1116-1128.  doi: 10.31497/zrzyxb.20170668
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    Reasonable compensation standard for water-saving irrigation technology can obtain a more positive response and improve policy effectiveness. In theory, the external benefits generated by water-saving irrigation technology are the basis of the compensation policy design. Taking Minqin County as an example, this paper quantified the external benefits of water-saving irrigation technology adopted by the choice experiment and random parameters Logit model, then calculated the compensation standard according to bargaining ability of the stakeholders. The results show that: 1) Both urban and rural residents of Minqin County all hope to improve the regional ecological environment by implementing water-saving irrigation technology. The annual willingness to pay of urban residents is 1 006.99 yuan if all arable land adopts high-efficiency water-saving irrigation technology in the next 10 years and the indicators restore to the best level designed in this article, and that of rural residents is 661.36 yuan. It indicates that the external benefit of technology adoption is obvious, thus the annual total external benefits is 50.96×106 yuan, around 1 052.25 yuan/hm2. 2) Accorrding to the natural environment of Minqin County and the adaptability of different technologies, if adopting drip irrigation technology, the reasonable standard should be around 789.15 yuan/hm2. Compared with the compensation standard of 150 yuan/hm2 in Gansu Province, the current water-saving irrigation technology compensation is too low to maintain farmers’ interests and lead to inadequate policy response. It is suggested that, a complete cost-benefit accounting system should be built which incorporates the external benefits to enhance the fairness of compensation policy. And a precision compensation should be implemented according to technology types and the area to increase financial fund utilization efficiency. Although this study provides a feasible way to quantify the external benefit of water-saving irrigation technology, Minqin County is one of the main sources of dust storms in China, benefits brought by its improved ecological environment for the residents outside the region (e.g., sandstorms reduction, etc.) is not included in the accounting of external benefits. Therefore, in the following study of cost-benefit analysis of water-saving irrigation technology, it is necessary to further explore the benefits of the residents outside the implementing region, so that quantitative results of external benefits can be more comprehensive.
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    Study on Integrated Water Quality Index and Its Application in Water Resources Assets Assessment in Shenzhen
    YANG Meng-chan, YE You-hua, ZHANG Yuan, CHEN Long, ZHANG Yi
    2018, 33 (7):  1129-1138.  doi: 10.31497/zrzyxb.20170657
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    Exploring the connotations of natural resources balance sheets is one of the major decisions the central government made on the Third Plenary Session of the 18th Central Committee to evaluate environmental performance of government leaders. Natural resources assets assessment techniques serve as a fundamental support for the application of natural resources balance sheets and the establishment of ecological damage liability scheme. Shenzhen, a burgeoning city located within the Pearl River Delta, is confronted with essential water problems ranging from water pollution to water shortage. Evaluating the monetary value of water resources with qualitative and quantitative methods could provide a unified approach to examine and compare water resources status at various spatial and temporal scales. Monthly sewage treatment data of Shuitou, Kuichong and Henggang water plants in Shenzhen in 2013 and 2014 have been collected. By analyzing the inlet and outlet water quality in each water plant with comprehensive pollution indice and principal component analysis method, the comprehensive water quality index which can be used to assess local water quality in Shenzhen is defined with parameters of key pollutants including TN, NH3-N, TP, COD, BOD5 and SS and is used to assess the value of local water resources in Shenzhen. Moreover, replacement cost is calculated. The link between comprehensive water quality and replacement costs is studied to construct the valuation model which can assess the value of Shenzhen landscape water and drinking water. The result indicates that it costs 0.6 yuan/t and 0.1 yuan/t to improve one unit of comprehensive water quality of landscape water resource and that of drinking water resource, respectively. Besides, it costs 1.05 yuan/t to store drinking water annually. Dapeng Peninsula, lying in east cost of Shenzhen, is selected to carry out the case study. The comprehensive water quality of all six main rivers and five major water reservoirs that supply water in Dapeng Peninsula is assessed. Accumulated surface runoff of the catchment areas and water retention capacity in 2015 are used to calculate the quantity of landscape water resource and drinking water resource. The results show that, in 2015, the value of landscape water resource and drinking water resource in Dapeng Peninsula is 3.60×108 yuan and 0.35×108 yuan, respectively.
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    Resource Ecology
    Theoretical Discussion on Planning and Design of Major Ecological Engineering
    XU Guo-jin, XIE Yong-sheng, LUO Han, MENG Min
    2018, 33 (7):  1139-1151.  doi: 10.31497/zrzyxb.20180092
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    Ecological problems have become a major barrier to the sustainable economic and social development in China. The main way to solve the ecological problems is to carry out ecological governing projects. Reverting Cropland to Forest and Grassland Project is the most typical case among the many major ecological projects implemented in China. However, because the theoretical research chronically lags behind the demands of production practices, the project has to be implemented, adjusted and improved simultaneously. The paper analyzed the main problems and the corresponding countermeasures taken by government at different stages of Reverting Cropland to Forest and Grassland Project and indicated that the ecological problems are the external manifestations of internal conflicts of economic and social systems. The ecological governance projects should not only solve the problems of ecological degradation and damages, but also solve internal economic and social conflicts which might induce ecological problems. Eco-engineering planning and design requires the theoretical support from related disciplines such as ecology, economics, and sociology. At the beginning of major eco-engineering planning and design, it is necessary to take into account the technical reserves, project costs, project achievement stability (the degree that the internal conflicts of economic and social system are solved), promotion, comprehensive benefits, collocation of policies, laws and regulations and other issues. The objectives of considering these factors are to achieve the ideal effect of “both internal and external governance”. All above theoretical methods may avoid the risks and wastes brought by simultaneous government, correction and summary and ensure the realization of the aims of the project.
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    Research on Evaluation Method and Model of Ecological Technology: The Design of Theoretical Model
    HU Xiao-ning, XIE Xiao-zhen, GUO Man-cai, WANG Ji-jun
    2018, 33 (7):  1152-1164.  doi: 10.31497/zrzyxb.20180164
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    Ecological technology plays an important role in mitigating the process of ecosystem degradation. However, the research of ecological technology lacks scientific and systematic evaluation method and model. After summarizing the methods and models which can be used for the evaluation of ecological technology, the paper put forward the “three stage evaluation method” based on ecological technology itself, its application effect, and its coupling relationship with the benefit, which are qualitative evaluation method, semi quantitative evaluation method, and quantitative evaluation method. With the continuous deepening of the understanding of a certain ecological technology and the continuous enrichment of data collection, the “three stage evaluation method” could be used to evaluate the ecological technology from the coarse to the fine, from qualitative to quantitative. At different cognitive stages of ecological technology, the theoretical model of ecological technology evaluation with different scenarios was established by regression analysis. One regression model was established at the stage of “qualitative evaluation”; seven regression models were established at the stage of “semi quantitative evaluation”; ninety-five regression models were established at the stage of “quantitative evaluation”. By establishing regression models in different situations, each stage reveals the relationship of the ecological technology elements is different index systems, realizes the thought of modular evaluation, and then obtains the comprehensive value of ecological technology evaluation. Three main problems of evaluation model were pointed out: attribute data digitization, overlap of index information and data imbalance. It was suggested that the regression model of ecological technology evaluation should be established on the basis of comprehensive consideration of setting the dummy variable, Lasso variable selection and data balance. The regression analysis evaluation model established in this study is based on existing ecological technology evaluation database and the experience of expert evaluation and is an objective evaluation model. The model could reduce the interference of subjective factors and make an objective evaluation on the ecological technology. The evaluation method and model of ecological technology established in this study could not only evaluate the existing ecological technologies, but also evaluate the innovative use of new technologies or existing technologies, so as to provide scientific basis for “bringing in” and “going out” of the ecological technologies all over the world.
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    Analysis of the Coupling Mechanism of Agricultural Industry-resources System in De-farming Regions of Northern Shaanxi Province Based on Structural Equation Model—A Case Study of Wuqi County
    CHENG Si-min, WANG Ji-jun, GUO Man-cai, LI Mao-sen, QIAO Mei, ZHAO Xiao-cui
    2018, 33 (7):  1165-1178.  doi: 10.31497/zrzyxb.20180272
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    The agricultural industry-resources coupling mechanism affects the coupling effect and regulates the coupling path of agricultural industry-resources system by changing the direction and intensity of the utilization of the agricultural resources. Using structural equation model, we analyzed the survey data from 497 households of Wuqi County in 2016, a typical area of de-farming regions. It is verified that policy, information (technology, market), agricultural resources and agricultural industry are the basic components and important driving factors of the agricultural industry-resources system coupling mechanism, and Wuqi County has formed a relatively steady multi-dimensional chain coupling mechanism. Through this mechanism, the agricultural industry has developed to a certain extent. However, it only utilizes the manifest value of resources, which hampers the optimization of the coupling relationship of agricultural resources and agricultural industry. The total standardized path coefficient of economic benefits is 0.112, and the path coefficient between the industry and economic benefit is only -0.047. From the perspective of the driving factors’ interaction, the one-way effect between agricultural industry and agricultural resources and the lack of part of the system chain network indicated that the current coupling mechanism cannot effectively support the benign operation of agricultural industry-resource system. For example, the economic function of forest-grass ecosystems is not fully investigated, and the resources allocation have not reached the optimal status. Therefore, a new benign coupling mechanism should be built next through the optimized combination of policy, information (technology, market), agricultural resources and agricultural industry so as to realize the optimal coupling of agricultural industry-resources system in Wuqi County and promote the construction of ecological civilization in the de-farming area.
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    Study on the Synergic Relationship between Grain for Green and Agricultural Eco-economic Social System—A Case Study in Ansai County
    LI Yue, WANG Ji-jun, LIU Pu-ling, CHENG Si-min, LI Mao-sen, QIAO Mei
    2018, 33 (7):  1179-1190.  doi: 10.31497/zrzyxb.20180107
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    The synergic relationship between Grain for Green (GGP) and agricultural eco-economic social system is an important issue in hilly regions of Loess Plateau, however, there are only a few researches involved in this topic. An indicator was established for revealing this relation in this paper. By selecting indicators of synergic relationship between GGP and agricultural eco-economic social system, a coupling degree model was established for describing the synergic relation. The synergic relation could be divided into four stages: 1) When GGP and agricultural eco-economic social system promote and develop collaboratively, the coupling degree is 0°≤θ<90°. 2) When they are contrary, the coupling degree is 90°≤θ<180°. 3) When they are in disorder, the coupling degree is 180°≤θ<270°. 4) When their development is inhibited, the coupling degree is 270°≤θ≤360°. Stage 3 is generally theoretical results and will not appear under the constraints of policy and influence of farmers’ behaviors, whereas stage 2 and 4 may appear in short term. Taking An’sai County in loess hilly and gully region of Shaanxi Province, China as an example, the synergic process was analyzed. From 1995 to 2014, the comprehensive indices of the GGP and the agricultural eco-economic social system in Ansai County increased significantly, the coupling degree was 33.59°-174.79°. The synergic relationship successively passed through stage 2 and stage 1, and is currently in the decline period of stage 1. It is indicated that Ansai County needs to further optimize its industrial structure in order to improve the effective utilization rate of the resources in this area, improve the quality of forest through rational layout of species structure of forest, and promote the coordinated development of the GGP and the agricultural eco-economic social system. This study laid a foundation for research on the collaboration between the GGP and the agricultural eco-economic social system.
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    Mapping the Changes in Supply and Demand of Carbon Sequestration Service: A Case Study in Beijing
    MENG Shi-ting, HUANG Qing-xu, HE Chun-yang, YANG Shuang-shu-ma
    2018, 33 (7):  1191-1203.  doi: 10.31497/zrzyxb.20171155
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    Carbon sequestration service provided by terrestrial ecosystem can mitigate climate change by directly absorbing atmospheric CO2. The balance between the supply and demand of carbon sequestration service is crucial for sustainable development in urban areas. However, spatially explicit and quantitative investigation of the changes in the supply and demand of this ecosystem service is relatively rare. In this study, the CASA model was adopted to measure the net primary productivity to represent the supply of carbon sequestration service. Meanwhile, the IPCC Guideline Inventory as well as the carbon metabolism method were used to measure the anthropogenic CO2 emissions to represent the demand of carbon sequestration service. Then, the balance of the supply and demand of carbon sequestration service in 2000 and 2013 were analyzed. The results showed that the supply of carbon sequestration service in 2000 was in short, the overall supply/demand ratio being 53.5%. Spatially, the demand of the service was far beyond the supply of the service in the central districts whereas the situation was opposite in the northern and western districts. In 2013, the gap between the supply and demand of the service was even larger that the supply/demand ratio dropped to 38.5%. Spatially, the gap between the supply and demand was widened in the central districts. The widened gap was mainly due to the increase in CO2 emissions accompanying with urbanization process. Specifically, CO2 emissions from household use and transportation contributed most to the increase. Therefore, it is highly recommended to enhance ecological conservation, improve the efficiency of energy consumption and accelerate the transformation of industrial structure for a more sustainable development path in Beijing.

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    Dynamic Changes and Driving Factors of Three Dimensional Ecological Footprint in Yulin
    YANG Yi, HU Die
    2018, 33 (7):  1204-1217.  doi: 10.31497/zrzyxb.20170658
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    Yulin is rich in energy but fragile in ecology. It is an important area for ecological engineering. It is necessary to analyze the status of natural capital stock and flow in Yulin and reveal the causes of natural capital occupation for the study of environment protection and sustainable development in ecological fragile areas. Basing on the calculation of ecological footprint per capita, ecological carrying capacity per capita, ecological deficit per capita and ecological pressure index in Yulin during 2005-2014, the paper describes the relationship between natural stock capital occupation and natural flow capital consumption through the depth and size of ecological footprint and studies the factors driving the ecological footprint changes with Partial Least Square (PLS) model. The results showed that the per capita ecological footprint in Yulin increased from 2.684 hm2/cap to 5.932 hm2/cap during 2005-2014, where the energy consumption accounted for the highest contribution. The ecological pressure index showed an overall increase from 1.387 to 1.894, except in 2013. The ecological footprint depth was 1.889 in 2005 and reached 2.380 by 2014, which means that a region as 2.380 times large as Yulin is needed to support the resource depletion in Yulin. The ecological footprint size increased from 1.421 hm2/cap in 2005 to 2.492 hm2/cap in 2014, where the ecological footprint size in 2013 increased significantly. In 2014, the consumption of capital stock in Yulin was 1.380 times of the amount of capital flow. The results of PLS model show that the factors affecting ecological footprint are mainly economic growth and social consumption. Yulin is facing severe ecological pressure, and energy consumption is the main reason for the rise of ecological pressure. The per capita ecological carrying capacity increased by 61.81% over the past 10 years, indicating that the implementation of ecological construction project plays an effective and positive role in improving the ecological carrying capacity. The consumption rate of capital stock in Yulin is faster than the rate of capital flow, and the substantial reduction of natural capital stock has seriously hindered the renewal of capital flow. These conclusions are of practical significance for the coordinated natural capital utilization and economic development in Yulin as well as provide a reference for natural capital utilization accounting in ecologically fragile areas.
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    Resource Evaluation
    Risk Assessment of China’s Preponderant Metals’ Supplying Global Demand
    WANG Chang, SONG Hui-ling, ZUO Lü-shui, SUN Jing
    2018, 33 (7):  1218-1229.  doi: 10.31497/zrzyxb.20170579
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    With the development of technological revolution and industrial transformation, the global supply and demand situation of metal resources have undergone significant adjustments. The United States, Japan, European Union and other major developed countries continue forcing China to open the preponderant metal supply in the existing multilateral trading system. Evaluating the risk of China’s preponderant metals’ supplying global demand is significant to guarantee the national metal resource security. Based on defining the scope of China’s preponderant metals, this paper gives a quantitative assessment on the risk of China’s preponderant metals’ supplying global demand from three dimensions: reliability, sustainability and affordability. The results show that: 1) The overall supply risk of China’s preponderant metals is high. Indium and bismuth are in high risk, having risk scores over 80; Antimony, germanium, barium, magnesium, tungsten and rare earth are in mid-high risk, having risk scores between 60-80; only gallium and strontium are in mid-risk, having risk scores between 40-60. 2) The reliability risk of barium is the highest which is 81.88, followed by the reliability risk of antimony which is 81.32, and rare earth has the lowest reliability risk which is only 42.42. Indium has the highest sustainability risk which is 81.80, while antimony has the lowest sustainability risk which is 69.46. Indium also has the highest affordability risk which is up to 100, followed by bismuth which has the affordability risk score of 89.23, and barium has the lowest affordability risk which is just 33.96. 3) With the rapid development of emerging industries, the supply risk of antimony, germanium, barium, magnesium, tungsten, indium and bismuth will increase in 2025. More severe supply circumstances will be faced by China’s preponderant metals.
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    Spatial Pattern of Low-benefit Conversion of Cultivated Land in China from 2000 to 2010
    ZHANG Bing-qi, GUO Jing, YU Xi, LI Qiang, CHEN Jin
    2018, 33 (7):  1230-1243.  doi: 10.31497/zrzyxb.20170940
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    The conversion from cultivated land to another land use type with relatively low benefit has multiple effects on food security and ecological system. To reveal the spatial patterns of this conversion among the first decade of the 21st century in China, in this paper, the conversion from cultivated land to grassland, shrub land and bare land was firstly defined as “low-benefit conversion of cultivated land”. Then, this kind of low-benefit converted land in China from 2000 to 2010 was extracted based on GlobeLand30 and the low-benefit conversion of cultivated land at the patch and county scale was mapped. The proportionality, regional difference and aggregation of spatial distribution were analyzed by multiple approaches and the effects of terrain conditions on low-benefit conversion and the relationship between 2000's original proportion of cultivated land and low-benefit conversion were revealed. The results showed that: 1) The low-benefit conversion rate of cultivated land was only 1.5% for the whole country, but the spatial distribution was very disproportion. At the county scale, more than 70% of the low-benefit conversion occurred in only 16 out of the 2 365 counties and the cultivated land area of these 16 counties accounted for less than 20% of that of the whole country. 2) The regional differentiation of low-benefit conversion showed close relationship with the three terrain ladders in China: regions on the second step particularly in the agro-pastoral transition zones suffered the most serious low-benefit conversion problem of cultivated land; in the Qinghai-Tibet Plateau, counties with very high low-benefit conversion rate and counties with very low rate alternated with one and another; for cultivated land on the third step, the low-benefit conversion rate was very low, but there were still a few high low-benefit conversion clusters in Liaodong Peninsula, Zhejiang and Guangdong coastal areas. 3) For the whole country, the low-benefit conversion rate of cultivated land increases as the altitude increases, and so do regions in which the slope is smaller than 15°, but circumstances when the slope is bigger than 15°are complex. 4) The impact of low-benefit cultivated land conversion on agricultural development depends on local farmland resource endowments. Land use efficiency of the main agricultural areas in China was higher as results showed that low-benefit conversion rate in these areas is low; although in some areas in the Qinghai-Tibet Plateau and the northern Inner Mongolia, the low-benefit conversion rate was very high, the proportion of cultivated land is small, which will not cause large-scale low-benefit conversion of cultivated land. Indeed, counties of which the low-benefit conversion rate and the proportion of cultivated land are both at medium or high levels, should be considered as areas with serious low-benefit conversion problems so as to be paid high attention.
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    Drought Trends over the Terrestrial China in the 21st Century in Climate Change Scenarios with Ensemble GCM Projections
    MO Xing-guo, HU Shi, LU Hong-jian, LIN Zhong-hui, LIU Su-xia
    2018, 33 (7):  1244-1256.  doi: 10.31497/zrzyxb.20170666
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    There are great uncertainties in drought predication because of climate change. Based on climate change scenarios projected by six GCMs in CMIP5 project, the spatio-temporal patterns of drought indices (Palmer Drought Severity Index, PDSI) over the terrestrial China in the 21st century in IPCC RCP 4.5 and RCP 8.5 scenarios are evaluated. Due to climate warming and precipitation variability, the drying trends are predicted to be prevailing in the 21st century over the country. It is shown that frequency, duration and intensity of drought will all be aggravated significantly, especially in the RCP 8.5 scenario. Compared to the baseline, the drought frequency will increase 1.5 and 3 times in 2050s and 2090s, respectively in RCP 4.5. In RCP 4.5, the drought duration will extend 0.3 and 1.1 month longer, and drought intensity will aggravate 9.1% and 26.9% in 2050s and 2090s, respectively. Long duration droughts will be more frequent in northern China, and the drought intensity will be aggravated in the Northeast China. By separating the effects of precipitation and temperature on PDSI, it is recognized that air warming results in the increase of drought frequency in southern part, while precipitation increases drought frequency slightly. In northern China, even though the precipitation increases significantly, the effect of air warming still overtakes the effect of precipitation, giving rise to more serious drought condition. In the light of drying trends in climate change scenarios, precautious measures and policies for mitigation and avoidance of drought disasters should be highlighted.
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    Evaluation of Drought Monitoring Indices Based onMulti-source Data in Southwest China
    HE Min, SONG Li-sheng, WANG Zhan-peng, GU Qing, WANG Da-ju, GUO Bo
    2018, 33 (7):  1257-1269.  doi: 10.31497/zrzyxb.20170526
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    Drought is one of the costliest natural hazards and its impacts on economic sectors and people are significant and widespread. However, drought is hard to be monitored appropriately since they are caused by the combination of anomalies in precipitation, temperature and the overall status of surface water and ground water supplies in a region. In this study, remote sensing based data, including MODIS ET, GRACE datasets, and climate datasets are used to calculate multiple drought indicators including SPI (Standardized Precipitation Index), ESI (Evaporative Stress Index), ETI (Evapotranspiration Index) and TWSC (Terrestrial Water Storage Changes). Then these drought indicators were used to track the drought events in Southwest China during 2005-2014. The results showed that all of the indicators can capture the droughts which occurred in the past decade, and the correlation coefficient between the computed SPI and ESI is the highest which is greater than 0.43 (P<0.01), compared with the correlation coefficients between other indicators. In addition, TWSC is more sensitive to widespread severe droughts and is more variable during fall and winter. However, ESI can capture the spatio-tempral distribution of the droughts in 2006, 2009 to 2010 and 2011 more accurately than SPI, ETI and TWSC, even without any input of rainfall data. Here, ESI responds to variability of soil moisture and vegetation water content which are introduced by the variations of precipitation and radiation load and is a useful complement for drought monitoring in regions where rainfall data are spare or unreliable.
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    Spatio-temporal Variation of Near-surface Temperature Lapse Rates over the Northwestern Tibetan Plateau
    SUN Cong-jian, LI Wei, LI Xin-gong, ZHANG Zi-yu, CHEN Ruo-xia, CHEN Wei
    2018, 33 (7):  1270-1282.  doi: 10.31497/zrzyxb.20170669
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    The lapse rate of near surface air temperature is an important parameter in hydrologic and climatic simulations, especially in the high mountainous areas without enough observations. Based on the long-term meteorological measurement data (1951-2013) and near surface air temperature (Tmin, Tave, and Tmax) measured by self-established weather stations during 2012-2016, this study evaluates the spatial and temporal variations of near surface temperature lapse rate (βlocal) over the northwestern Tibetan Plateau. The results show that: 1) The near surface air temperature lapse rate has a spatiotemporal distribution pattern over the northwestern Tibetan Plateau and the constant environmental temperature lapse rate (0.65 ℃/100 m) throughout the year cannot represent the variability of the temperature-elevation relationship in complex terrain areas. The temperature has a significant downward trend as the elevation increases. LRTave, LRTmin, LRTmax in two regions showed different spatial variations. The LRTave, LRTmin, LRTmax at the meteorological stations are higher than the LRTave, LRTmin, LRTmax at the mountain observation stations. The LRTmin shows significant spatial variation, while the LRTmax has smaller spatial variation. 2) A significant seasonal variation can be observed in this region. At the meteorological stations, the trend is that higher values are observed in spring and summer and lower values in winter. As for the mountain observation stations, the LRTave, LRTmin, LRTmax are higher in summer and lower in winter. The LRTmax at the meteorological stations and the LRTmin at the mountain observation stations have significant seasonal variations. 3) The variations of βlocal for Tmax and Tmin in two regions exhibit similar monthly variation characteristics, that βlocal is lower in months of winter and spring and higher in other months. Monthly βlocal for Tmin is higher than Tave and Tmin at the meteorological stations through the whole year. The highest βlocal for Tmax and Tmin occurs in April, while the highest βlocal for Tave occurs in June. At the mountain observation stations, the highest βlocal for Tmax occurs in October, while the highest βlocal for Tave and Tmin occurs in April. 4) A significant increasing trend of βlocal for Tave and Tmin was observed after 1990. The difference of βlocal for Tmin before and after 1990 is more obvious. The differences of Tmax at different elevations before and after 1990 are weak. 5) The spatial and temporal variations of βlocal over the northwestern Tibetan Plateau are linked to geographic differences and climate factors. In addition, the controlling factors for the lapse rate in two regions are different. This research will provide a theoretical basis for quantitative researches of temperature distribution characteristics and mountain ecosystem’s response to climate change in mountain areas.
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    The Effect of Water Fluctuation on the Contents of Soil Cu, Zn, Cr and Cd at the Riparian Area of Three Gorges Reservoir
    YANG Dan, XIE Zong-qiang, FAN Da-yong, XIONG Gao-ming, ZHANG Ai-ying
    2018, 33 (7):  1283-1290.  doi: 10.31497/zrzyxb.20170637
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    To reveal the contents of soil heavy metals that affected by periodic water fluctuation in the riparian soil of Three Gorges Reservoir, the contents of soil Cu, Zn, Cr and Cd in different flooding gradients were analyzed, and the sources of the four heavy metals and the relationship between the contents of those heavy metals and water level fluctuation were further discussed. The results showed that: 1) The contents of soil heavy metal in the riparian area of different flooding gradients were significantly different. The contents of Cu, Zn and Cd were higher in long submerged soil than in short submerged and non-flooded soil, whilst soil contents of Cr had slight change at different water levels. 2) Except Cr, the contents of Cu, Zn and Cd were closely related to values of SOM and pH in soil, but there was only a weak correlation between pH and SOM. 3) PC 1 and PC 2 explained 93.47% of the total variance in soil Cu, Zn, Cr and Cd. Cu, Zn and Cd had the greatest loading of 0.962, 0.967, 0.925 in PC 1, respectively, whilst the load value of Cr in PC 2 was 0.998. The results suggested that: 1) Heterogeneity in the sources and flow directions of heavy metals determined the different heavy mental contents in different submerged soils. Long-term flooding significantly increased the contents of soil Cu, Zn and Cd, but had little effect on Cr. 2) Cr in this region was originally derived from soil erosion and bedrock weathering, while Cu, Zn and Cd originated from the anthropogenic activities on the farmland surface and the sediment of suspended particles from upstream water.
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