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  • Articles
    Regional Energy Efficiency in China Based on a Three-Stage DEA Model
    HUANG Dechun, DONG Yuyi, ZHANG Changzheng, LIU Bingsheng
    2014, 5(2): 97-104. https://doi.org/10.5814/j.issn.1674-764x.2014.02.001
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    Energy is the material basis for social development and is closely related with the economy. Energy shortage, a low utilization rate of energy and the deterioration of the environment have become the main restrictions of economic development in China. Therefore, studying energy efficiency has a practical significance for developing a harmonious and sustainable energy economy and building a conservation-minded and harmonious society. Here, based on the three-stage DEA model we analyzed the energy efficiency of 29 provinces in China in 2009, set up an evaluation index system of energy efficiency to compare differences in energy efficiency among regions and provide regions with theoretical guidance to adjust energy consumption strategy and improve energy efficiency. We divided technical efficiency into pure technical efficiency and scale efficiency, analyzed energy efficiency with its numerical value and added environment variables to perfect the results. We found that scale efficiency is overestimated before eliminating external factors and environment variables and pure technical efficiency is underestimated. To solve this problem, regions should expand the scale of the enterprises and pay more attention to energy efficiency. The scale returns of most provinces in the third stage are increasing (except Shandong province), which shows that many enterprises are too small to reflect the economy scale. Therefore, all regions except Shandong should increase their energy inputs to obtain the economy scale of energy utilization. From a regional perspective, eastern energy efficiency is highest and western is the lowest. All regions should increase the size of enterprises to realize the scale economy. Central and western regions in China should strengthen mutual cooperation, bring into play their respective advantages, exploit new energy and new technology and improve the utilization ratio of energy.
  • Articles
    Sand-fixing Function under the Change of Vegetation Coverage in a Wind Erosion Area in Northern China
    GONG Guoli, LIU Jiyuan, SHAO Quanqin, ZHAI Jun
    2014, 5(2): 105-114. https://doi.org/10.5814/j.issn.1674-764x.2014.02.002
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    Using meteorological and remote sensing data and changes in vegetation cover during the wind erosion season in northern China, a revised wind erosion equation was applied to evaluate spatiotemporal variation in soil erosion and conservation since the 1990s, and to reveal the effects of the change of vegetation coverage on the wind erosion control service. The results showed that average soil erosion in northern China between 1990 and 2010 was 16.01 billion tons and was decreasing. The most seriously eroded areas were mainly distributed in large desert areas or low cover grasslands. Most wind erosion occurred in spring, accounting for 45.93% of total wind erosion. The average amount of sand fixation service function for northern China between 1990 and 2010 was 20.31 billion tons. Given the influence of wind erosion forces, the service function for sand fixation cannot effectively highlight the role of sand fixation from the ecosystem itself. The retention rate of service function for sand fixation reveals the role of the ecosystem itself. The distribution characteristics of the soil retention rate are similar to vegetation cover, which shows a gradual decrease from southeast to northwest in the study area. Improved spring vegetation cover was observed mainly on the Loess Plateau, Qinghai-Tibet Plateau, in northern Hebei, eastern Inner Mongolia and northeast China after the implementation of ecosystem projects. The soil retention rate in most areas showed a significant positive relationship with grassland vegetation in spring (r > 0.7, p < 0.01). The increments of ecosystem service function for various ecological systems are different. Increments for the grassland ecosystem, forest ecosystem, farmland ecosystem and desert ecosystem are 2.02%, 1.15%, 0.99% and 0.86%, respectively.
  • Articles
    Increased CO2 Emissions from Energy Consumption Based on Three-Level Nested I-O Structural Decomposition Analysis for Beijing
    ZHANG Wang, SHEN Yuming, ZHOU Yueyun
    2014, 5(2): 115-122. https://doi.org/10.5814/j.issn.1674-764x.2014.02.003
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    The first task in ensuring a reduction in CO2 emissions is to quantitatively measure the factors and their effect size on increasing CO2 emissions due to fossil fuel consumption. An extension of the buying and import-noncompetition economy-energy-CO2 emission input-output model was designed to analyze CO2 emission increases for Beijing from 1997-2007. The increase in CO2 emissions because of energy consumption was broken down into nine kinds of effects including the change in energy consumption intensity and structure, and economic scale expansion. We found that the effect of economic scale expansion such as consumption investment, export and selling were the main factors increasing CO2 emissions. The effect of the change in energy consumption intensity was the dominant factor reducing CO2 emissions. CO2 emissions increased rapidly from 2002. The first increase in carbon emissions was related to the service industry, adjustment in industrial structure and the priority given to tertiary industries. High energy consumption manufacturing was the industrial branch driving CO2 emissions; the main industry driving CO2 emission reductions was the energy industry. The new round of industrialization with ‘high carbon’features meant that CO2 emissions increased rapidly from 2002-2007. The quantity and direction of the nine focal effects varied across industries and different industrial sectors.
  • Articles
    Glacier and Lake Changes across the Tibetan Plateau during the Past 50 Years of Climate Change
    LI Zhiguo
    2014, 5(2): 123-131. https://doi.org/10.5814/j.issn.1674-764x.2014.02.004
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    In this paper, recent glacier and lake changes research on the Tibetan Plateau was reviewed. Emphasis was placed on a discussion of the relationship between glacier shrinkage and lake change. In the context of global climate change, the glaciers of the Tibetan Plateau have generally retreated, while the lakes have generally expanded. First, the research on glacial terminal retreat, glacial area and volume variations across the Tibetan Plateau over the last few decades are reviewed and analyzed; the temporal-spatial change characteristics of the glaciers are discussed. Secondly, the lake area, volume and water level changes are reviewed and analyzed; the temporal-spatial change characteristics of the glaciers are discussed. The results indicate that the retreat speed in the outer edge of the Tibean Plateau was overall faster than that in the inland area. The areas and water levels of the lakes that are fed by glacial water increased. Finally, the limitations of the present studies and future work are discussed.
  • Articles
    Solar Radiation Climatology Calculation in China
    WANG Chenliang, YUE Tianxiang, FAN Zemeng
    2014, 5(2): 132-138. https://doi.org/10.5814/j.issn.1674-764x.2014.02.005
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    The Angstrom-Prescott formula is commonly used in climatological calculation methods of solar radiation simulation. Fitting the coefficients is carried out using linear regression and in recent years it has been found that these coefficients have obvious spatial variability. A common solution is to divide the study area into several subregions and fit the coefficients one by one. Here, we use ground observation data for sunshine hours and solar radiation from 1961 to 2010. Adopting extraterrestrial radiation as the initial value, Angstrom-Prescott coefficients are obtained by Geographically Weighted Regression at a national scale. The surfaces of solar radiation are obtained on the basis of the surfaces of sunshine hours interpolated by high accuracy surface modeling and astronomical radiation; results from spatially nonstationary and error comparison tests show that Angstrom-Prescott coefficients have significant spatial nonstationarity. Compared to existing research methods, the method presented here achieves a better simulation effect.
  • Articles
    A Seventeen-Year Quantitative Study of Succession in Central European Grassland
    ZHANG Yuanyuan, Johanna JÖRG, Carl BEIERKUHNLEIN, XUE Dayuan
    2014, 5(2): 139-147. https://doi.org/10.5814/j.issn.1674-764x.2014.02.006
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    The objective of this paper is to test three main hypotheses in grassland succession by using 17-year observational data: (ⅰ) species diversity increases during early pioneering stages; (ⅱ) the similarity rate of experimental plant communities increases along with the succession process (dissimilarity rate among plots decrease with succession age); and (ⅲ) plant communities in different field plots converge towards a quite similar composition during the initial years of succession. Results draw from quantitative statistics which including: the general development of plant communities, Shannon's H and E, Bray-Curtis dissimilarity and community turnover, indicate that after first 5 years of succession, species diversity rapidly becomes alike among all the plots. The average species number in all plots increased constantly from 8 to 25. Meanwhile, the total species number for all plots increased constantly from 23 to 55, accompanied by a steady decrease in Standard Deviation (S.D.) from 4.6 to 0.3. Additionally, dissimilarity of all stands in species composition decreased, indicating a clear trend towards a rapid convergence in species richness and composition. The most important effect of cessation of weeding is that the artificial diversity gradient from 1 to 16 species gets diminished by immigration in species poor plots.
  • Articles
    Forest Carbon Storage Trends along Altitudinal Gradients in Beijing, China
    XIAO Yu, AN Kai, YANG Yang, XIE Gaodi, LU Chunxia
    2014, 5(2): 148-156. https://doi.org/10.5814/j.issn.1674-764x.2014.02.007
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    Rapid growth in population and gross domestic product in Chinese urban regions such as Beijing has resulted in a large amount of CO2 emissions from fossil fuels. Forests are considered the most important carbon sink to offset these carbon emissions. In this study we estimated forest carbon storage in Beijing using forest inventory data and the biomass expansion factors method. We analyzed trends in the forest ecosystem and its fractions along altitudinal gradients. We concluded that broad-leaved forest is the main forest carbon pool in Beijing, and forest carbon is mainly stored in plains at an altitude of <60 m a.s.l. and in the low mountainous area at an altitude of 60-600 m a.s.l. Forest ecosystem carbon density in Beijing increases with altitudinal gradients but slightly decreases in regions at altitudes that range from 200-400 m a.s.l. Forest vegetation carbon density of the plain area at an altitude of <60 m a.s.l. is much higher than other areas, attributable to the high ratios of the plantation of Populus spp. and Larix principisrupprechtii with higher vegetation carbon densities than others and human practices such as fertilization and irrigation which are beneficial for vegetation carbon accumulation. The forest soil carbon density in Beijing also increases with increasing altitude, attributable to decreasing soil carbon output with altitude. Management practices such as understory cultivation, irrigation, fertilization and scarification directly accelerate carbon emissions from soil heterotrophic respiration which decreases with altitude. Soil erosion in areas that range from 200-800 m a.s.l. also decrease with altitude as management practices decrease. This study will underpin scientific knowledge for local forest managers to adopt more appropriate practices to protect forest ecosystems and to improve forest carbon storage.
  • Articles
    Changes in the Energy Consumption Carbon Footprint for Gansu Province
    JIAO Wenxian, ZHAI Manman, CHEN Xingpeng, JIA Zhuo
    2014, 5(2): 157-162. https://doi.org/10.5814/j.issn.1674-764x.2014.02.008
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    Energy consumption is one of the main human activities driving global climate change, and therefore research on the carbon footprint of energy consumption is of great significance. In this paper, concepts and methods relating to the carbon footprint of energy consumption were used to calculate total carbon footprint, carbon footprint of each type of energy, output value of the carbon footprint and its ecological pressure from 1990 to 2009 in Gansu Province, northwestern China. The ridge regression function within the STIRPAT model was applied to study the quantitative relationship between carbon footprint and economic growth and at the same time verify the existence of an Environmental Kuznets Curve. A decoupling index was introduced to further explore the dynamic relationship between economic growth and carbon footprint. We found that the total carbon footprint increased from 0.091 ha per capita in 1990 to 0.191 ha per capita in 2009 and followed a fluctuating rising trend. Coal and oil occupy the dominant position within the carbon footprint composition, while natural gas is of little effect. The output value of the carbon footprint increased from 11 800 CNY per ha in 1990 to 25 100 CNY per ha in 2009, representing an average annual growth rate of 4.1%. The ecological pressure intensity of the carbon footprint increased to 0.24 in 2009, and remains much lower than developed provinces Jiangsu and Shanghai, due to the vast area of woodland in Gansu. Development of a low-carbon economy in Gansu remains hindered by limited energy, a fragile ecological environment and irrational energy structure. Population and GDP per capita growth were the main factors driving the increasing carbon footprint; the impact of population is 3.47 times of that of per capita GDP. Regression analysis and decoupling index analysis have proved the existence of the Environmental Kuznets Curve for economic growth and carbon footprint, but 33 years are required to reach the inflection point.
  • Articles
    Regional Ecological Vulnerability Assessment of the Guangxi Xijiang River Economic Belt in Southwest China with VSD Model
    LI Pingxing, FAN Jie
    2014, 5(2): 163-170. https://doi.org/10.5814/j.issn.1674-764x.2014.02.009
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    The interactive effects of natural and human factors on ecosystems have been well studied, and the quantitative assessment of large-scale ecological vulnerability caused by natural and human factors is now one of the most active topics in the field. Taking the Guangxi Xijiang River Economic Belt in southwest China (GXEB) as a case study, we assess ecological vulnerability based on the Vulnerability Scoping Diagram (VSD) model. The indices system is decomposed into three sub objects, ten elements and 25 indicators layer by layer, which included factors from both natural and human fields. Results indicate that zones with lower, middle-lower, middle, middlehigher and higher vulnerability account for 11.31%, 22.63%, 27.60%, 24.39%, and 14.07%, respectively. The western and eastern parts of GXEB are more vulnerable than the central part and the mountain and urban areas are of higher vulnerability than the basins and river valleys. Compared with a vulnerability assessment based on natural factors only, it is concluded that human activities indeed cause the transition from naturally stable zones to vulnerable zones. The nature-dominated vulnerable zones are different with human-dominated ones in size and distribution, the latter being smaller, more scattered and distributed in urban areas and their surroundings. About 53% of total construction land is distributed in zones with middle and middle-higher ecological vulnerability; less vulnerable zones should attract construction in the future. Relevant suggestions are proposed on how to reduce vulnerability according to inducing factors. The VSD model has a significant advantage in the quantitative evaluation of ecological vulnerability, but is insufficient to distinguish nature-or human-dominated vulnerability quantitatively.
    • Reports
  • Reports
    An Analysis on the Ecological Value and Contribution of Agriculture in Tianjin City
    GONG Qianwen, MU Xiangli, WANG Limao, ZHOU Hong, GU Shuzhong
    2014, 5(2): 171-178. https://doi.org/10.5814/j.issn.1674-764x.2014.02.010
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    Agriculture has both economic value and non-economic value. The calculation of the non-economic value of agriculture has become a research hotspot in academic circles. This paper divides the value of agriculture into products production value and ecological value, and adopts an authoritative ecological value calculation idea, i.e. the method proposed by Costanza et al. in 1997 as the basis to calculate the ecological value of agriculture. However, the study has come under heavy criticism: for example, some data have major deviation, underestimating the ecological value of cultivated land while overestimating the wetland. XIE Gaodi et al. in 2003 came up with more reliable results to make up for the deficiency of the methods from Costanza et al. Referring to some of the results and on the basis of a questionnaire survey to 200 Chinese ecologists, this paper presented an equivalent factor table for evaluating the ecological service value (ESV) of China's ecosystem. Based on this table and the practical situation of Tianjin, the paper formulates an applicable calculation method for ecological value and actually calculates the ecological value of agriculture in Tianjin with official statistics. The results show that the actual value of the ecological value of agriculture in Tianjin in 2012 was 111.20 billion CNY, about triple of the economic value of agriculture (37.56 billion CNY) in the same year.
  • Reports
    Representation of Agricultural Best Management Practices in a Fully Distributed Hydrologic Model：A Case Study in the Luoyugou Watershed
    WU Hui, LIU Yongbo, LIU Junzhi, ZHU A-Xing
    2014, 5(2): 179-184. https://doi.org/10.5814/j.issn.1674-764x.2014.02.011
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    Agricultural Best Management Practices (BMPs) are effective ways to reduce agricultural nonpoint source pollution from their source area to receiving water bodies. Characterization of BMPs in a watershed model is a critical prerequisite for evaluating their impacts on water quantity and water quality in a complex system. However, limited research has reported about the representation of BMPs in fully distributed models. This paper presents a stepwise procedure for representation of several BMPs and assessment of their hydrologic impacts with a fully distributed model, SEIM (Spatially Explicit Integrated Modeling). A case study is conducted in the 73 km2 Luoyugou watershed located in the Loess Plateau of China, where rainstorm erosion accounts for more than 60% of annual sediment load in average. Three BMPs are selected in this study including (ⅰ) conversion from farmland to forest, (ⅱ) terrace, and (ⅲ) no-till farming. These management practices are represented in the model through the alteration of model parameters characterizing their physical processes in the field. The results of scenario assessment for a historical storm event showed that the maximum sediment reduction after terrace is about 97.3%, the average sediment reduction after no-till farming is about 9.5%, and the average sediment reduction after conversion from farmland to forest is 75.6%.
  • Reports
    Short-interval Land Use Change Detection with Microwave Remote Sensing Data
    CHEN Xiaoyue
    2014, 5(2): 185-192. https://doi.org/10.5814/j.issn.1674-764x.2014.02.012
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    As the fast economic development and urban expansion, it is difficult for traditional methods to monitor land use changes in short time interval. Moreover, remotely sensed data acquired by optical sensors is often limited by bad weathers and cloud cover. SAR images, such as RADARSAT-1, are an ideal tool for weather-proof observation on ground surface. This paper analyzed the results of land use change detections with time lags of 24, 48 and 72 days according to the period of acquisition dates of RADARSAT-1. The results need a compromise between accuracies and efficiencies related to the time lags. For most of the situation, it is sufficient of using a time lag of 24 days to obtain accuracy of 60% or above. In some cases of months, a time lag of 48 days is needed. For obtaining higher accuracies, longer time lag such as 72 days is needed.