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  • 2012 Volume 67 Issue 1
    Published: 20 January 2012
      
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  • Protection and Construction of the National Ecological Security Shelter Zone on Tibetan Plateau
    SUN Honglie, ZHENG Du, YAO Tandong, ZHANG Yili
    2012, 67(1): 3-12. https://doi.org/10.11821/xb201201001
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    The shelter function of Tibetan Plateau has an important effect on the ecological security in China, even in Asia. Under the joint influence of global change and human activities, ecosystem destabilizing and resources and environment pressure increasing emerge on the Tibetan Plateau, which have caused some problems, including significant glacier retreat, serious land degradation, aggravated soil erosion and water loss, increased threats to biodiversity along with decreased rare and specious biological resources, and natural disasters increasing. These problems have a great influence on regional ecological security shelter function on the plateau. Based on the relevant research and practical experience in ecological construction, some suggestions are proposed to strengthen ecological protection and construction of the national ecological security shelter zone on the Tibetan Plateau at present, namely, strengthening basic research on the Tibetan Plateau ecological shelter impacts and regional ecological security enhancement and climate change mitigation; developing the key technology of protection and construction of the national ecological security shelter zone on the plateau and demonstration; striving to set up a monitoring system of ecological shelter function, intensifying evaluation of protection and construction efficiency of ecological security shelter zone, perfecting evaluation systems and standards, and summarizing experience, so as to enhance the overall function of national ecological security shelter and to further take the initiative in dealing with global change.
  • Ecological Effects of Longitudinal Range-Gorge Land Surface Pattern and Its Regional Differentiation
    PAN Tao, WU Shaohong, HE Daming, DAI Erfu, LIU Yujie
    2012, 67(1): 13-26. https://doi.org/10.11821/xb201201002
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    The land surface pattern of Longitudinal Range-Gorge Region with towering mountains and deep valleys arranged vertically side by side has significant effects on physical environments and eco-geographical differentiation in Southwest China. Based on 1:50,000 DEM data, monthly meteorological and hydrological records, NDVI and NPP derived from MOD13 and MOD17, together with 1:1,000,000 vegetation types map, we select surface atmospheric water vapor content, precipitation, aridity/humidity index, and surface runoff as water indices; air temperature and accumulated temperature as temperature indices, and solar radiation as a heat index to study the hydrothermal pattern, regional differentiation of ecosystem structure and function and main influencing factors. The ANUSPLIN model, wavelet analysis, GIS spatial analysis and landscape pattern analysis were used to reveal the effects of land surface pattern on eco-geographical regional differentiation. Results show that the water, temperature and heat have significant differences along the latitudinal direction with intermittent difference and longitudinal direction with continuous extension, which reflects the special "corridor-barrier" effect of longitudinal range-gorge terrain, in which the vertical mountain and valleys on the surface of natural material and energy transport mainly showed significant north-south corridor and diffusion effects and the role of east-west barrier and barrier effect. The longitudinal range-gorge terrain also have important impacts on the spatial pattern of vegetation landscape diversity, ecosystem structure and function, which is the main influencing factor affecing the spatial distribution of vegetation landscape diversity and ecosystems pattern. Wavelet variance analysis reflects the spatial anisotropy of environmental factors as well as NDVI and NPP. The wavelet coherence reveals the spatial distribution of NDVI and NPP influencing factors, and also the quantitative degree of control. Conclusions believe that the longitudinal range-gorge land surface pattern is the main influencing factor of the eco-geographical elements. Under the interaction of the zonality law and the non-zonality "corridor-barrier" effects, the spatial differentiation formed in the eco-geographical system.
  • The Priority Pattern for Managing the Potential Ecological Risks Associated with Heavy Metals of the Top Soil on Yancheng Coast
    FANG Shubo, JIA Xiaobo, AN Shuqing, ZHENG Zheng
    2012, 67(1): 27-35. https://doi.org/10.11821/xb201201003
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    The spatial geostatistical characteristics of the 5 heavy metals (Cr, Cu, Ni, Zn and Cd) of the top 106 soil samples on Yancheng coast, were studied with the aid of GS+ software. With ARCGIS 9.2, the Hakanson risks index (HRI), which was a synthetic reflection of the potential ecological risks of heavy metals, was interpolated. A computational approach, including NDVI, determining Euclidean Distance to the main anthropogenic impact sources, and land use reclassification, was proposed to detect the ecological hotspots, with clarification of different levels of potential ecological risks through integrating the Hakanson index computing. The conclusions can be drawn as follows. Metals (Cr, Cu and Cd) had strong spatial autocorrelations, while Ni had modest spatial autocorrelations, and the spatial autocorrelation of Zn could not be modeled. Through the semivariogram functions analysis, the exponential model could best model the spatial autocorrelations of Cr and Ni, while spherical model could best model Cu and Cd. There was a high heterogeneity of HRI, and areas including the Dafeng Natural Reserve areas, near the Liangduo River Gate, the areas between Dafeng Habour and Simaoyou Gate, and areas north to the Sheyang Habour, had a relatively low HRI, while areas including areas neighboring Sheyang Habour and Sheyang Salt Field had a high HRI. The priority ecological hotspots with medium and low heavy metal ecological risks were finally proposed.
  • Magnetic Properties of Dustfall in Lanzhou City and Its Environmental Significance
    FENG Hua, LIU Xiuming, LV Bin, MA Mingming, LI Pingyuan, LIU Zhi, ZHAO Guoyong, MAO Xuegang
    2012, 67(1): 36-44. https://doi.org/10.11821/xb201201004
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    Environmental magnetic measurements were carried out on the samples of Lanzhou dustfall. These samples were collected monthly during April 2007 to June 2011 at Lanzhou University. The magnetic parameters (χlf, SIRM, χARM, k-T curves and magnetic hysteresis parameters) indicate a high concentration of magnetic minerals in Lanzhou, dominated by pseudo-single domain (PSD) magnetite, but also contain maghemite, lepidocrocite and hematite. They mainly come from pollution of human activities. The parameter χlf can effectively denote the concentration variations of magnetic mineralogy of polluted dustfall. Previous studies have shown that χlf value in Lanzhou dustfall has significant variations during the year. The value of χlf is distinctly high in the heating months, while low in other months. Although March is also in the heating period, its χlf value is obviously lower than other that of heating months, which might be due to the unique inversion phenomenon of Lanzhou basin: low intensity of ground inversion being conducive to the diffusion of pollutants. April and May have the lowest values throughout the year, and the reasons could be 1) low intensity of ground inversion, and 2) dilution effect of frequent occurrence of dust storms (with low χlf) in these months. The air quality of Lanzhou has been greatly improved in winter for the last four years. In 2010, the χlf value is 38% lower than that in 2007, indicating that environmental magnetism can effectively monitor urban pollution.
  • Changes of Spring Phenodate in Yangtze River Delta Region in the Past 150 Years
    ZHENG Jingyun, GE Quansheng, HAO Zhixin, ZHONG Shuying, MA Xiang, ZHANG Xuezhen
    2012, 67(1): 45-52. https://doi.org/10.11821/xb201201005
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    Based on phenological records extracted from Chinese historical dairies, the series of spring phenodate in the Yangtze River Delta region of China since 1834 is reconstructed. Together with the temperature and phenology observation data, the interpretation of the phenodate variation to temperature change is also analyzed. The results are shown as follows. (1) Spring phenology in the Yangtze River Delta region is gradually delayed during 1834-1893 and greatly advances after 1893; and exhibits inter-decadal fluctuation during 1900-1990 and greatly advances after 1990. The latest year of the spring phenodate is delayed by 27 days and occurs in 1893, while the earliest year is advanced by 17 days and occurs in 2007. (2) Correlation coefficient between spring phenodate in the Yangtze River Delta region and temperature (previous December to March and January to March) is higher significant up to the level at 99.9% with the value over -0.75 and -0.80, respectively. The variation of spring phenodate well indicates the change of temperature from previous winter to early spring, especially from January to March. These results will provide a data basis for the further study on temperature change reconstruction using multi-proxy data, including phenological records during historical times.
  • Spatial Differences of Changes in Spring Vegetation activities across Eastern China during 1982-2006
    ZHANG Xuezhen, DAI Junhu, GE Quansheng
    2012, 67(1): 53-61. https://doi.org/10.11821/xb201201006
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    To understand the spatial differences of changes in spring vegetation activities across eastern China during 1982-2006, we analysed the mean spatial pattern of Normalized Differences Vegetation Index in spring and spatial pattern of linear trend of changes in spring NDVI, identified the models of spring vegetation activities changes through the clustering analysis and calculated the correlations coefficients between spring NDVI and temperature and precipitation variations. It was found that vegetation activities decreased from south to north with an abrupt decrease at 34?-39? N. The transition belt was derived from natural vegetation distribution, but the south-north grads in the transition belt were enhanced by anthropogenic cropland. Across eastern China, spring vegetation activities had trends of significant increase in the North China Plain, Hulun Buir area and Dongting Lake Plain, and the North China Plain had the greatest rate of 0.03 NDVI per decade (r2 = 0.52; p < 0.001); while, spring vegetation activities had trends of significant decrease in the Yangtze River Delta and Pearl River Delta, and Yangtze River Delta had the greatest rate of -0.02NDVI per decade (r2 = 0.24; p = 0.014). The vegetation activities variations across eastern China had evident spatial heterogeneities. The spatial heterogeneities were primarily featured by differences between a decreasing trend in the Yangtze River Delta and Pearl River Delta and an increasing trend in other areas. The secondary differences were the differences between persistent increasing trend during 1982-2006 in the North China Plain, Hulun Buir area and south of Yangtze River to South China and breaking increase after 1997-1998 in Northeast China, eastern part of Inner Mongolia Plateau and lower reaches of the Yangtze River. The third and lower level differences were interannual variabilities differences among the regions.
  • Assessing the Impacts of Climate Variability and Human Activities on Streamflow in the Water Source Area of Baiyangdian Lake
    HU Shanshan, ZHENG Hongxing, LIU Changming, YU Jingjie, WANG Zhonggen
    2012, 67(1): 62-70. https://doi.org/10.11821/xb201201007
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    As the largest wetland in the North China Plain, Baiyangdian Lake plays an important role in maintaining water balance and ecological health of NCP. In the past few decades, the decreasing streamflow in Baiyangdian Basin associated with climate variability and human activities has caused a series of water and eco-environmental problems. In this study, we quantified the impacts of climate variability and human activities on streamflow in the water source area of Baiyangdian Lake, based on analyses of hydrologic changes of upper Tanghe catchment from 1960 to 2008. Climate elasticity method and hydrological modeling method were used to distinguish the effects of climate variability and human activities. The results showed that the annual streamflow decreased significantly (P > 0.05) by 1.7 mm/a and an abrupt change was identified around the year 1980. The quantification results indicated that climate variations accounted for 38%-40% of decrease in streamflow, while human activities accounted for 60%-62%. Therefore, human activities played a dominant influence in the decline of the streamflow in the water source area of Baiyangdian Lake. To keep the ecosystem health of Baiyangdian Lake, we suggest that minimum eco-water demand and integrated watershed management should be guaranteed in the future.
  • Runoff Variation in the Three Rivers Source Region and Its Response to Climate Change
    ZHANG Yongyong, ZHANG Shifeng, ZHAI Xiaoyan, XIA Jun
    2012, 67(1): 71-82. https://doi.org/10.11821/xb201201008
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    Runoff in the three time scales (non-flooding season, flooding season and annual period) was simulated and tested from 1958 to 2005 at Tangnaihai (Yellow River source region: YeSR), Zhimenda (Yangtze River source region: YaSR) and Changdu (Lancang River source region: LcSR) by hydrological modeling, trend detection and comparative analysis. Also, future runoff variations from 2010 to 2039 at the three outlets were analyzed in A1B and B1 scenarios of CSIRO and NCAR climate model and the impact of climate change was tested. The results showed that the annual and non-flooding season runoff decreased significantly in the YeSR, which decreased the water discharge to the middle and downstream of the Yellow River, and intensified the water shortage in the Yellow River Basin, but the other two regions were not statistically significant in the last 48 years. Compared with the runoff in the baseline (1990s), the runoff in the YeSR will decrease in the following 30 years (2010-2039), especially in the non-flooding season. Thus the water shortage in the middle and downstream of the Yellow River Basin will be serious continuously. The runoff in the YaSR will increase, especially in the flooding season, thus the flood control situation will be severe. The runoff in the LcSR will also be greater than the current runoff, and the annual and flooding season runoff will not change significantly, while the runoff variation in the non-flooding season is uncertain. It will increase significantly in the B1 scenario of CSIRO model but decrease significantly in B1 scenario of NCAR model. Furthermore, the most sensitive region to climate change is the YaSR, followed by the YeSR and LcSR.
  • Spatial-temporal Patterns of Drought Risk across the Pearl River Basin
    XIAO Mingzhong, ZHANG Qiang, CHEN Xiaohong
    2012, 67(1): 83-92. https://doi.org/10.11821/xb201201009
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    Monthly precipitation data of 42 rain stations over the Pearl River basin for the period 1960-2005 were analyzed to classify anomalously dry conditions using the 6-month standardized precipitation index. Trends of the SPI-based droughts were detected using Mann-Kendall technique. The results are shown as follows. (1) The western part of the Pearl River basin tends to be dryer and the eastern part tends to be wetter. Enhancing droughts are observed mainly in November, December, and January, and increasing wetting tendency in January and July. Meanwhile drought duration and severity show insignificant trends. (2) The drought risk across the Pearl River basin is very high and the highest drought risk is found mainly in the eastern part of the basin. Besides, the results also show that long-lasting droughts are highly probably the severe droughts. Moreover, the drought risk is greatly increased in the eastern Pearl River basin, when droughts of higher severity occur in the Pearl River basin. These results may imply tremendous challenges for the water resources management in the Pearl River basin, particularly the eastern part of the Pearl River basin. The second return period represents many situations of drought, so the result of the second return period may be more robust.
  • Spatial-temporal Changes of Land Surface Emissivity in China from 2001 to 2010
    WANG Xinsheng, XU Jing, LIU Fei, GAO Shoujie
    2012, 67(1): 93-100. https://doi.org/10.11821/xb201201010
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    The land surface emissivity is one of the important parameters in temperature inversion from thermal infrared remote sensing. With the aid of MOD11C3 of Terra-MODIS L3 level products, we obtained 10-year spatial-temporal data sets of land surface emissivity in China from 2001 to 2010. The results show that Northwest China's desert region has the minimum land surface emissivity in China, with little seasonal variations. In contrast, there are significant seasonal variations in land surface emissivity in Northeast and Northwest China, Qinghai-Tibet Plateau, the Yangtze River Basin, East and South China. In winter, the land surface emissivity is relatively high in Northeast and Northwest China. The land surface emissivity of Qinghai-Tibet Plateau maintains a lower value from November to March, while it is higher in other months. The land surface emissivity of the Yangtze River Basin, East China, South China and Sichuan Basin decreases from July to October, and peaks in August. Land surface emissivity values could be divided into five levels: low emissivity (0.6163-0.9638), low-moderate emissivity (0.9639-0.9709), moderate emissivity (0.9710-0.9724), moderate-high emissivity (0.9725-0.9738), and high emissivity (0.9739-0.9999). The percentages of regions with low emissivity, low-moderate emissivity and moderate emissivity are, respectively, about 20%, 10% and 20%. The moderate-high emissivity regions makes up of 40%-50% of Chinese surface land area. The inter-annual variation of moderate-high emissivity region is also distinct, with two peaks (in spring and autumn) and two troughs (in summer and winter). The inter-annual variation of high emissivity regions is very significant, with a peak in winter (10%), while only 1% and 2% in other seasons. There is clear relationship between the spatial-temporal distribution of Chinese land surface emissivity and temperature: the higher the emissivity, the lower the temperature, and vice versa. Emissivity is an inherent property of any object, but the precise value of its emissivity depends greatly on its surrounding environmental factors.
  • Urban Surface Heat Flux Inversion Based on Infrared Remote Sensing and the Relationship with Land Cover
    LIU Yue, Shintaro Goto, ZHUANG Dafang, KUANG Wenhui
    2012, 67(1): 101-112. https://doi.org/10.11821/xb201201011
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    This study extracted urban surface heat flux parameters based on PCACA model using ASTER infrared remote sensing image, and then analyzed the impacts on urban surface heat flux and energy balance from different land cover types in the experimental area of Kumagaya City, Saitama Prefecture of Japan. The results indicate that this method on application PCACA model to estimate surface flux in urban areas is feasible. This algorithm can greatly reduce the complexity of the underlying surface structure of the urban areas of surface heat flux estimates, and decrease the uncertainty of the results. The study found that urban and rural areas of different land cover types on the surface heat flux were significantly different. According to urban land use and cover types, Bowen ratio is industrial, residential, traffic, establishment, dry field, public green and water body in a descending order. In the same weather conditions, surrounding vegetation and urban areas compared to urban land has a high sensible heat flux, the lower the latent heat flux, and the higher Bowen ratio. The urban surface sensible heat flux and Bowen ratio was significantly higher than that of the surrounding vegetation surface, leading to urban surface heating of the lower atmosphere. This is an important mechanism for the formation of urban heat island effect.
  • Land Use and Land Cover Change in Watershed of Guanting Reservoir Based on Complex Network
    WU Pengfei, GONG Huili, ZHOU Demin
    2012, 67(1): 113-121. https://doi.org/10.11821/xb201201012
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    Based on six Landsat images from 1978 to 2009 of Guanting Reservoir located in northwest Beijing, this paper interprets land use maps. In the analysis of this paper, the transfer matrix of land use and cover change (LUCC) is studied as a network, among which land use types are nodes and conversions between different land use types are connections. From the overall perspective of land use system, the complex network methods of degree, betweenness and average shortest path are applied to identify the major changes in land use types, to assess stability of land use system and to analyse the changes from natural ecosystem to artificial ecosystem. The findings are shown as follows. First, in the time scale of recent 30 years, dry farming lands, natural grasslands and artificial water bodies are always the major changing land use types in transfer matrixes and the LUCC process has been dominated by these three land use types. Second, the average shortest path values of five transition matrix networks are all less than 1.5, indicating that land use system becomes more active yet less stable but the average shortest path values of these five networks present an increasing trend, indicating a more stable development of land use system. Third, in recent 30 years, natural ecosystem has been gradually replaced by artificial ecosystem, manifesting a reduction of 62.1% in natural grassland areas and a 65.1% reduction in waste land areas.
  • Analyzing the Turns of David Harvey's Scholarship: A Case Study on the Innovation of Geographical Thought
    YE Chao, CAI Yunlong
    2012, 67(1): 122-131. https://doi.org/10.11821/xb201201013
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    David Harvey transformed from a positivist to a radicalist, and to a Marxist in the end. The turns of his scholarship are an important phenomenon in the western geography, and a typical case of innovation in geographical thought and epistemology. According to analyzing some representative works of Harvey, this paper focuses on epistemological problems, particularly the transformation of Harvey's view on space because of 'space as a keyword' in geography in accordance with Harvey himself. It is argued that his scholarship career mainly at least experienced three stages:the view of the relative but multidimensional space, the view of uniting'social- processspatial- form' and the view of historical-geographical materialism spatial system. The three stages are corresponding with Harvey's scholarship career as a positivist, a radicalist, and finally a Marxist. On the basis of the statements of Harvey himself, this article sums up that there are some reasons why he fulfilled the shifts, i.e. the drastically changing social and political conditions, his individual interests and gifts, his working circumstances, the need for geography at that time, the other occasional factors. Harvey's academic transformation implies significance and inspiring for Chinese geographers. The geographers of China should treat correctly logical positivism geography, be confronted with key social practical problems and inquire into the deep reasons and build theories. Based on the principles of 'independent spirit, free thinking', Chinese geographers can contribute more to academy and society.