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    The pH value and electrical conductivity of atmospheric environment from ice cores in the Tianshan Mountains
    DONG Zhi-Wen, ZHANG Meng-Jun, LI Zhong-Qi, WANG Fei-Teng, WANG Wen-Bin
    Journal of Geographical Sciences    2009, 19 (4): 416-426.  
    Abstract2249)      PDF (482KB)(131)      

    Electrical Conductivity Measurement(ECM) from ice core is a representative index for atmospheric environmental change.The pH value and ECM from three shallow ice cores(each 3.85 m,231 ice samples total) on Glacier No.1 at the headwater of Urumqi River,Glacier No.48 in Kuitun area,and Miaoergou Glacier in Hami area in the eastern Tianshan Mountains,western China,were measured and analyzed for atmospheric environment records research.Ice core record shows that the changing trend of pH and ECM in three sites in recent years is different:ECM in Kuitun increases with the ice depth change,but ECM in Hami and Urumqi Glacier No.1 ice cores show a decreasing trend.Average ECM value in Hami is much larger than other two sites,just as the dust concentration and ions concentration are also very high in this site.ECM records in all three sites are mainly affected by aerosol mineral dust of Central Asia,and correlative coefficients of ECM and mineral ions such as Ca2+,Mg2+,Na+ are all significantly high.The pH value and ECM are also significantly high correlative coefficients in the eastern Tianshan Mountains.Comparison between the eastern Tianshan Mountains and other sites in western China,and Polar Regions,shows that the difference of ECM can very well reflect the spatial difference of worldwide atmospheric environment.

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    Cited: Baidu(11)
    Method for calculating ecological water storage and ecological water requirement of marsh
    LI Li-Juan, LI Jiu-Yi, LIANG Li-Jiao, LIU Yu-Mei
    Journal of Geographical Sciences    2009, 19 (4): 427-436.  
    Abstract649)      PDF (274KB)(72)      

    As one of the most typical wetlands,marsh plays an important role in hydrological and economic aspects,especially in keeping biological diversity.In this study,the definition and connotation of the ecological water storage of marsh is discussed for the first time,and its distinction and relationship with ecological water requirement are also analyzed.Furthermore,the gist and method of calculating ecological water storage and ecological water requirement have been provided,and Momoge wetland has been given as an example of calculation of the two variables.Ecological water use of marsh can be ascertained according to ecological water storage and ecological water requirement.For reasonably spatial and temporal variation of water storage and rational water resources planning,the suitable quantity of water supply to marsh can be calculated according to the hydrological conditions,ecological demand and actual water resources.

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    Cited: Baidu(16)
    Natural environment suitability for human settlements in China based on GIS
    BIAN Zhi-Meng, YANG Yan-Zhao, ZHANG Dan, TANG Yan
    Journal of Geographical Sciences    2009, 19 (4): 437-446.  
    Abstract858)      PDF (439KB)(95)      

    With the degeneration of environment and acceleration of urbanization,human environment has attracted great attention worldwide.This paper sets up the Human Settlements Environment Index(HEI) model and evaluates the natural environment suitability for Human Settlements in China based on GIS technology.The results show that the HEI of China decreases from southeast to northwest in general,HEI is significantly correlated with population density at grid size and the correlation coefficient(r) between them reaches 0.93,which indicates that natural environment suitability for Human Settlements has a significant influence on population distribution.Most people in China mainly concentrate in areas with high natural environment suitability.The total suitable area is 430.47×104 km2,which accounts for nearly 45% of the total land area in China,while the proportion of people living in the area reaches 96.56%.With a population density of 18 people per square kilometer,the critical area is the transitional region for people to live in China.The critical area covers 225.11×104 km2 with a population of 41.12 million.The non-suitable area covers 304.42×104 km2 with a population of only 2.49 million.

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    Evaluation of dissolved inorganic nitrogen eliminating capability of the sediment in the tidal wetland of the Yangtze Estuary
    WANG Jun, CHEN Zhen-Lou, WANG Dong-Qi, SUN Xiao-Jing, HU Shi-Yuan
    Journal of Geographical Sciences    2009, 19 (4): 447-460.  
    Abstract610)      PDF (685KB)(6)      

    Estuarine wetlands serve as a natural barrier to remove the land-generated pollutants and attenuate the pollutant load from the land to the sea.As one of the most important estuarine wetlands,the Yangtze estuarine wetlands have attracted particular interests in the biogeochemical studies of nutrients.The objectives of this study were to characterize the seasonal and spatial distribution of dissolved inorganic nitrogen(DIN) fluxes across the sediment-water interface;to calculate the total DIN fluxes in a year and different seasons;and to evaluate the DIN removing capability of the sediment in the tidal wetlands of the Yangtze Estuary.The spatial distribution of DIN fluxes shows complicated seasonal variations and spatial differences.The annual DIN fluxes range from-22.22 mmol N m-2 h-1 to 19.54 mmol N m-2 h-1,with an average of-1.48±1.34 mmol N m-2 h-1.The tidal wetlands in the Yangtze Estuary behave as a source of water DIN in spring when DIN is released from sediment into overlying water,and the released amount of DIN is 1.33×104 tons of nitrogen(T N).In summer,autumn and winter,the sediment absorbs the DIN from the overlying water,and the absorbed amounts of DIN are 4.36×104 T N,6.81×104 T N and 2.24×104 T N,respectively.The average amount of DIN in overlying water of the Yangtze Estuary is 52.6×104 T N yr-1,and the perennial average amount of DIN absorbed from the overlying water by the sediment is 12.1×104 T N yr-1.The annual DIN elimination rate of the tidal wetlands was 23.0%.

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    Cited: Baidu(6)