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    25 October 2005, Volume 20 Issue 5 Previous Issue    Next Issue
    Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    Spatial and Temporal Variation of Precipitation over Ten Major Basins in China between 1956 and 2000
    CHEN Yu, GAO Ge, REN Guo-yu, LIAO Yao-ming
    2005, 20 (5):  637-643.  doi: 10.11849/zrzyxb.2005.05.001
    Abstract ( )   PDF (266KB) ( )   Save
    In the context of 1956~2000 monthly rainfall data at 743 stations over China,regional normal mean condition,inter-decadal change and trends of annual and seasonal precipitation are analyzed at drainage basins scale.The changes of mean precipitation between 1956~1979 and 1980~2000 periods were compared for 10 drainage basins.The results show that the preci-pitations are less with larger variability and water resources are insufficient and more instable in river basins of northern China.As for basins in southern China,precipitation is abundant with small variability and water resources are relatively sufficient and stable.In the recent 45 years,the trends of annual precipitations for the northern basins have been generally negative,with the decrease of the 1990s being the most remarkable.On the other hand,the increasing tendency of precipitation is a major feature for the southern basins.In the 1990s,the mean annual precipitations of the southern basins exceed mostly those of the 1980s,particularly in the areas south of the Yangtze River.For seasonal precipitation,obvious decreasing tendencies mainly occurred in summer and autumn,while winter and spring experienced a slight increasing tendency for most of the basins.In the last 20 years,the tendencies of precipitations in most of the basins are similar with those for the 1956~2000 period.The river basins in Northwest China are the only basins among the ten where precipitation of the four seasons all experienced an increasing trend.
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    Study on the Distribution Characteristics and Developing Potential of Cloud Water Resource in Liaoning Province
    ZHOU De-ping, GONG Fu-jiu, ZHANG Shu-jie, Ban Xian-xiu
    2005, 20 (5):  644-650.  doi: 10.11849/zrzyxb.2005.05.002
    Abstract ( )   PDF (232KB) ( )   Save
    There is a lack of fresh water in China and the contradictions between population growth and economic development with shortage of fresh water,become increasingly sharpened,hence affecting seriously the economy in some regions and social sustainable and healthy development in our country.Artificial precipitation-enhancement is an efficient approach to develop and make use of cloud water resource in the air and lighten water resource's shortage.Usual radiosonde data,cloud and surface precipitation data offered by the meteorological observation net of Liaoning Province are used in this paper,and the distribution and developing potential of Liaoning cloud water resource is calculated and analyzed.The results indicated that: (1)The total cloud water resource in Liaoning Province is about 483 billion m3,being basically at the average level of the whole country,and the it is about 285.7 billion m3 in summer,or more than 59% of the years total.(2)The unit area available cloud water resource is the highest in the southeastern mountain regions of Liaoning,being about 500×104m3/km2;and central plain and inland coastal zone come the second,being about 350×104m3/km2;and the least is in the northwestern part,being only about 260×104m3/ km2.(3)From May to October,the amount of cloud water resource in the precipitation processes persisting of over 2h accounts for 89% and we can modify these processes by rocket.The amount of cloud water resource in the processes persisting of over 5h makes up 48%and there are quite a great deal of seeding operation opportunities by aircraft.(4)Generally,the ratio of the occurrence frequency of the precipitation processes unsuitable for operating because of their short-time persistence or heavy rainfall intensity is about 31%,and the amount of cloud water resource of these processes is about 20% of the total.(5)The precipitation processes causing about 80% of the amount of cloud water resource is adequate for artificial operating.If the efficiency of artificial precipitation is 10%,then about 8.0 billion m3 of cloud water can be developed in Liaoning every year.If the efficiency of artificial precipitation is increased by 25%,then about 9.0 billion m3 of cloud water can be developed each year. Thus,it is possible to exploit Liaoning's cloud water resource to lighten water resource's shortage.
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    Water Supply Development Strategy and Source Water Area Protection in Shanghai: Patterns, Problems and Prospects
    CHE Yue, YANG Kai, WU E-nuo, YUAN Wen
    2005, 20 (5):  651-659.  doi: 10.11849/zrzyxb.2005.05.003
    Abstract ( )   PDF (328KB) ( )   Save
    Most Chinese cities in the process of urbanization are going through drinking water crisis,and source water protection is regarded as the first barrier to keep drinking water safe.Shanghai is one of the largest and most important economic centers of China,which is located in tidal river network,and is surrounded with abundant water resources.With rapid urbanization and industrialization,water quality of river network decreased and the water shortage owning to the low water quality appeared recently.The conflict between rapid economic development and source water protection is obvious,and the difficult status of source water area due to poor water quality has been the key limiting factor affecting regional ecological safety and sustainable development.Changjiang Estuary and the upstream of Huangpu River are the main source water areas in Shanghai.And there are many small scale source water areas in the suburbs of Shanghai.Based on the data about water resources and water environment,the characteristics of water resources and source water area distributions are discussed,and the main problems in current water resource utilization,water environmental protection and water supply pattern are identified. The spatial variation and periodic evolvement of water resources and water environmental quality are analyzed.This paper indicated that Shanghai's water supply systems are facing many challenges,and there are some problems in the upstream of Huangpu River,Changjiang Estuary and large numbers of dispersed source water areas in the suburb.Those problems are listed below:(1)regional development and water quality of the upper reaches influenced source water quality of the upstream of Huangpu River;(2)salt water intrusion and pollutant discharge influenced the development of Changjiang Estuary;(3)distributions of waterworks and serious river pollution in the suburbs influenced the safety of drinking water.So a strategic framework of new water supply systems composed of Changjiang Estuary and the upstream of Huangpu River was developed.Some small scale waterworks should be adjusted,and a new reservoir in Changjiang Estuary should be built up.Finally,the upstream of Huangpu River protection strategy based on watershed management and ecosystem management method was proposed,and the Changjiang Estuary protection strategy based on river basin management method and avoiding salt water measure was proposed.
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    Isotopic Characteristics of Precipitation and Throughfall of Alpine Shrubs on Balang Mountains in Wolong
    CUI Jun, AN Shu-qing, XU Zheng, XU Qing, WANG Zhong-sheng, LIU Shi-rong
    2005, 20 (5):  660-668.  doi: 10.11849/zrzyxb.2005.05.004
    Abstract ( )   PDF (306KB) ( )   Save
    Stable hydrogen(H) and oxygen(O) isotopic characteristics of precipitation and through-fall of alpine shrubs were studied in this paper.The summer Local Meteoric Water Line (LMWL) of Balang Mountains is δD=9.93δO+26.07,which is different from the Global Meteoric Water Line (GMWL),exhibiting higher slope and intercept values.This was attributed to the influences of cold air mass on the isotopic composition of rainfall during late August and early September.The amount effect and temperature effect of precipitation appeared alternately,indicating that the alternate domination of the amount of rainfall and temperature resulfed in the variation of precipitation isotopic composition.Moreover,the isotopic effects of H were more significant than those of O.This was because the fractionation of H isotopes is stronger than that of O isotopes in nature and H isotopes are more sensitive to the variation of environmental factors than O.So,H isotopes are more useful in the research of forestry hydrology.Besides,there were apparent differences between the throughfall of different plots,which is the result of different evaporation rates of water droplets and fog-intercepting capacity caused by different vegetation structures.There was a strong correlation between the δ value of rainfall and throughfall.The δ value of throughfall is not necessarily larger than that of rainfall,indicating that there are more factors influencing the isotopic composition of throughfall other than the evaporation rate of water droplets and the fog-intercepting capacity of vegetation.A good understanding of these factors will be of great significance to the further application of stable isotopic techniques in the research of forestry hydrology.
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    Effects of Old-fields Successional Revegetation on Soil Moisture in Hilly Loess Region of Northern Shaanxi
    DU Feng, SHAN Lun, LIANG Zong-suo, TAN Yong
    2005, 20 (5):  669-678.  doi: 10.11849/zrzyxb.2005.05.005
    Abstract ( )   PDF (150KB) ( )   Save
    In this article,effects of revegetation on soil moisture of old-fields were analyzed using multiregression and path analysis,based on once investigation of 0~300cm soil moisture of 17 sites with different abandonment years,11-times (once measurement of 0~500cm in growth season and ten times of 0~300cm)measurements of 10 sites,each measurement interval in profile is 20cm.The results show that:(1)As the related factors,such as aboveground biomass,vegetation coverage,soil organic matter etc.changed after abandonment,their effects to soil moisture content and fluctuation may vary in different post-abandonment stages.The measurements agree with the above facts,and confirmed that actually in local region,soil moisture content of old-fields tends to decrease,whilst fluctuation,denoted by standard deviation of moisture content,tends to increase after abandonment.(2)Soil moisture content and fluctuation can be estimated by topographic factors(slope gradient,slope facing and altitude),soil factors(bulk density of topsoil,organic matters) and vegetation factors(aboveground biomass,coverage),in which contents of top layers and fluctuation in root layers are determined mainly by communities coverage,while the aboveground biomass contributed most to the fluctuation of deeper layers.Both the communities cover and the aboveground biomass act mainly through its relative large positive and direct effect. (3)We found that down flux of soil moisture exists in the 260~300cm layer, deduced from the significant positive relationship between the difference of moisture reserves in 260~300cm and accumulative rainfall.In other words,the 260~300cm in profile is not the critical layer of rainfall compensation and plant usage,in our measurements,rainfall may seep beyond 300cm.This implies that evapotranspiration may be over estimated if calculated from the 0~300cm soil moisture content.So the accumulated leakage calculated by the 280~300cm soil moisture content is used as a supplement adjustor in multiregression to the estimated evapotranspiration.The evapotranspiration can be estimated by vegetation coverage,aboveground biomass,moisture flux in deep layer,slope gradient and direction,and topsoil bulk density.In which the primary influencing factor to communities evapotranspiration is aboveground biomass,vegetation coverage ranks the second.
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    Study on the Wind Energy Resource Division in Guangdong Province
    MAO Hui-qin, SONG Li-li, HUANG Hao-hui, ZHI Shi-qun, LIU Ai-jun
    2005, 20 (5):  679-683.  doi: 10.11849/zrzyxb.2005.05.006
    Abstract ( )   PDF (292KB) ( )   Save
    In the recent 30 years,wind power has become an important energy source because of its contribution to the alleviation of the environmental pollution,and more and more countries have paid attention to the development of this new energy source.By the end of 2004,the total capacity of wind power in the whole world is 47 616.4MW with an increasing rate of 21.2% in 2004.The capacity of china is 764.0MW,and the increasing rate is 34.7% in the corresponding period. Wind power in China has stepped into a fast developing stage.However,in China,the main wind resource reference for choosing wind farm states is the wind energy division performed by ZHU Rui-zhao in the 1980's which can only give a rudiment result for China's wind energy distri-bution,because its data is from weather stations with spatial distance up to 80km.Since wind is a stochastic variant which varies with terrain,underlying characteristics,weather phenomenon and so on,wind energy resource division with high spatial resolution is urgently needed for choosing sites of large-scale wind farms in order to meet the fast developing wind power market.Guangdong Province is rich in wind resource and has good investment environment,and its wind power development takes the lead throughout the country.According to the meteorologic data of 86 stations and the short-term data of 72 observation towers in coastal zone of Guangdong,based on Surfer8.0 and Citystar3.0,wind energy parameters at the 1km×1km grid are calculated.Macroscopic wind energy division and the division specially for choosing sites of wind farms are performed.The exploitable capacity in theory and practice at 10m height above the ground are 7.50×104MW and 5.89×103MW,respectively.The result of this study can provide a scientific and detailed reference for macroscopic project planning and microscopic site choosing for large wind farms for wind power development.
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    The Wind Energy Potential in Jilin Province, China
    Hartwig Dobesch, CHEN Shen-bin, Hung Viet Tran, LIU Ji-ping
    2005, 20 (5):  684-689.  doi: 10.11849/zrzyxb.2005.05.007
    Abstract ( )   PDF (310KB) ( )   Save
    The wind energy potentials of the Jilin Province,China,is estimated by means of certain algorithms and procedures for wind turbine siting,digital terrain maps and digitalisation of surface roughness on the basis of certain land use maps.For the necessary meteorological input data only such were used easily available from the ordinary meteorological network.On a grid of nearly 1km × 1km the mean annual wind speed and the wind power density 60 m above ground level were mapped.Generally, the most favourable wind resources are found in the central and western part of the province.High wind resource areas in the southern and eastern part are located on ridges or crests and mountain summits.
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    Soil Copper Accumulation under Different Land Use Types-The Case of Beijing
    ZHENG Yuan-ming, CHEN Tong-bin, ZHENG Guo-di, CHEN Huang, LUO Jin-fa, WU Hong-tao, ZHOU Jian-li
    2005, 20 (5):  690-696.  doi: 10.11849/zrzyxb.2005.05.008
    Abstract ( )   PDF (269KB) ( )   Save
    To investigate soil copper accumulation under different land use types,Cu concentra-tions of 609 soil samples from vegetable field,paddy field,orchard,greenbelt,cornfield and natural soils in Beijing were taken and analyzed.It was found that the concentrations of Cu with geometric mean 20.9mg/kg were much higher than the background concentration (18.7mg/kg),which indicated that atmospheric transportation was an important factor influencing the accumulation of Cu in the soils at large scale.Furthermore,some human activities,such as pesticides,livestock manures and landfill,would increase the concentrations of Cu in the soils rapidly at local scale.Combined with ANOVA analysis,Cu in the orchard showed the highest geometric mean concentration in 6 types, which was significantly higher than the mean concentrations of Cu in vegetable field,cornfield and natural soils.And the differences among the samples of orchard were also obvious,indicating the inhomogeneity of the spatial distribution and differences of the way and time of cultivation in different areas.Using the baseline (37.1mg/kg) as the criterion,the ratio of total samples beyond the limit was 5.6%.Compared with the total sample numbers of each land use type,the percentages of soil samples with the Cu concentrations over the baseline of Beijing soils were 29.2%,4.7%,4.2%,8.3% and 4.6% for orchard,vegetable field,paddy field,greenbelt and cornfield,respectively.The samples over the baseline of Beijing soils are mainly distributed in Changping and Chaoyang district.How to avoid the areas with serious pollution is an important problem in land use planning,especially in agricultural land use planning.
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    Main Grain Crops Structural Change and Its Climate Background in Heilongjiang Province during the Past Two Decades
    YUN Ya-ru, FANG Xiu-qi, WANG Yuan, TAO Jun-de, QIAO Dian-feng
    2005, 20 (5):  697-705.  doi: 10.11849/zrzyxb.2005.05.009
    Abstract ( )   PDF (424KB) ( )   Save
    Global warming during the 20th century,especially the impacts of the global warming in the past two decades,has been paid much attention worldwide.A case study is made in this paper on the relationship between change of main grain crops structure and global warming in Heilongjiang Province,Northeast China,based on the statistical data of agriculture and ground based climate data during 1980 to 2000.Wheat,corn and rice are the three main crops planted in this province,the varieties of which indicate the human's response to the climate change.K-Means analysis is employed in this paper.It is found that,with the climate warming,the seeded area of rice has increased from 2×105hm2 to 16.06×105hm2,that of wheat deduced from 20.379×105hm2 to 5.9×105hm2,and the area of corn has been escalating.Thus the planting structure has been changed from wheat and corn in domination to corn and rice in domination in the past 20 years.The relationship between the main crops structure and the global warming is very evident.The northern planting boundary of the rice in Heilongjiang Province has extended to 52°N at north,and been pushing towards the east.The borderline of corn advanced to the north.At the meantime,the seeded area of wheat retreated northward.Changes of the main grain crops structure lie on the warming up procedure in Heilongjiang Province under global warming,which proved that temperature change has influenced human society to a certain extent,and people began to adapt to the new environment by transferring the land use patterns.
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    An Aggregation Fractal Study on Spatial Structure of Tourist Scenic Spots Systems-A Case Study of Nanjing
    DAI Xue-jun, DING Deng-shan, XU Zhi-hui, LIN Lan
    2005, 20 (5):  706-713.  doi: 10.11849/zrzyxb.2005.05.010
    Abstract ( )   PDF (225KB) ( )   Save
    Applying the theory and methods of random aggregation fractal,this paper studies the spatial structure of the tourist scenic spots systems in Nanjing.The fractals present non-scaling and self-organization,and bear natural optimized structure;because the fractals present non-scaling,the random aggregation dimension is the characteristic parameter to measure the fractals.The evolution tendency of the tourist scenic spots systems is similar to Diffusion-Limited Cluster Aggregation mode.Based on the definition of Diffusion-Limited Cluster Aggregation,the author puts forward the method of random aggregation fractal to study the spatial structure of the tourist scenic spots systems.The tourist scenic spots systems' spatial structure present distinct random aggregated fractal structure and shows a self-organization optimized evolutive tendency,but there are different evolvement phases in different regions,accordingly.The degrees of tourist scenic spots systems' centripetence are different and all the systems' stourist scenic spots densities are degenerating from the center to the circumference.The value of random aggregation dimension is the criterion of the optimized trend of tourist scenic spots systems' spatial structure.
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    Ecological Damage Appraisal of Sea Reclamation:Theory, Method and Application
    PENG Ben-rong, HONG Hua-sheng, CHEN Wei-qi, XUE Xiong-zhi, CAO Xiu-li, PENG Jing-ping
    2005, 20 (5):  714-726.  doi: 10.11849/zrzyxb.2005.05.011
    Abstract ( )   PDF (421KB) ( )   Save
    Half of the world's population,production and consumption activities are concentrated in the coastal zone which accounts for only 10% of all land area.High density population areas have a deficit of space.Coastal human settlements can exploit their position by reclaiming tidal and shallow sea areas through sea reclamation. Sea reclamation by the coast usually means that the sea is filled with earth to create more useful land area.Sea reclamation,however,results in heavy losses to ecosystems of the immediate coastal environment.The coastal ecosystems services such as storing and cycling nutrients, filtering pollutants from inland freshwater systems,protecting shorelines from erosion and storms, regulating global hydrology and climate,accepting and assimilating waste and providing food and materials can be destroyed by the sea reclamation.The value of filled seas as production factors and ecological damage of sea reclamation must be integrated into the decision-making about the planning of sea reclamation to ensure the sustainable use of marine resources. In our paper,we identified the damage to marine and coastal ecosystems of sea reclamation at first,and then established ecological-economic models to estimate the ecological damage of sea reclamation and to assess the value of marine space as production factors to provide sound basis for policy formulation about regulating sea reclamation project.We applied the developed model in Xiamen and found that the values of filled seas for industrial zone and for commercial use were 48.82yuan/m2 and 1 251.4~1 572.04yuan/m2;the value of ecological damage of sea reclamation was 279yuan/m2.The present usage charge standard is so low that it did not include the full costs of sea reclamation and should be modified to 327.82 yuan/m2 for industrial use and 50%~55% of the adjacent land prices for commercial use.
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    The Change of Cultivated Land and Ecological Environment Effects Driven by the Policy of Dynamic Equilibrium of the Total Cultivated Land
    TAN Yong-zhong, WU Ci-fang, WANG Qing-ri, ZHOU Lian-qing, YAN Dong
    2005, 20 (5):  727-734.  doi: 10.11849/zrzyxb.2005.05.012
    Abstract ( )   PDF (61KB) ( )   Save
    Land policy is one of the most important driving factors affecting the use of land and the change of ecological environment.This paper analyzes the effects of the policy of dynamic equilibrium of the total cultivated land on the change of cultivated land and ecological environment effects in China.Firstly,the impacts of the policy on the quantity change of cultivated land are analyzed from occupying and supplementing cultivated land.Then,the impact of the policy on the comprehensive productivity of cultivated land is quantitatively analyzed by using index of cultivated land productivity.Finally,the effects of the policy on ecological environment are analyzed.The result indicates that this policy has an active effect on the change of cultivated land,presenting mainly in the following aspects:The tendency that non-agricultural constructions are taking too much cultivated land has been totally limited,the whole country and various provinces (municipalities,autonomous regions)have realized the equilibrium of occupying and supplementing cultivated land,and the farmland consolidation has been promoted.However,this policy has an opposite effect on the change of the quality of cultivated land.While the whole country has carried out the equilibrium of occupying and supplementing cultivated land,the comprehensive productivity of cultivated land was declining.At the same time,it has also negatively affected the ecological environment.On this basis,this paper advances some propositions of adjusting the policy,such as restudying the feasibility and necessity of the policy of dynamic equilibrium of the total cultivated land,replacing this policy with protecting and improving the comprehensive productivity of cultivated land,and adopting diverse specific measures according to the regional difference of land resources.
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    An Analysis of Touristic Ecological Footprint and Eco-compensation of Jiuzhaigou in 2002
    ZHANG Jin-he, ZHANG Jie, LIANG Yue-lin, LI Na, LIU Ze-hua
    2005, 20 (5):  735-744.  doi: 10.11849/zrzyxb.2005.05.013
    Abstract ( )   PDF (311KB) ( )   Save
    It is very important to establish a suit of eco-compensation system for natural reserve residents,and which is the key to acquire sustainable development for nature reserve.The paper puts forward the concept of touristic ecological footprint and its calculation model by taking Jiuzhaigou natural reserve as an example,calculates and analyses the tourists and residents ecological footprints.Based on the touristic ecological footprint,it constructs an eco-compensation estimate model for residents of the nature reserve.Four conclusions have been summarized:(1)The touristic ecological footprint of Jiuzhaigou is 0.061hm2 per capita in 2002.In comparison, extrapolating the footprint of a tourist to Jiuzhaigou (1.8 days) to 1 year,results in an area of 8.8817hm2 per capita in 2002, 9.27 times that of the average footprints 0.961 6hm2 of citizens of Jiuzhaigou. (2) Plus the tourist ecological footprint,the total ecological footprint of Jiuzhaigou in 2002 is 1.005 3hm2 per capita,ecological capacity is 1.202 6hm2 per capita,ecological remainder is 0.197 3hm2 per capita.(3)In Jiuzhaigou,the average tourist output of 1 hm2 ecological footprint is 8 643 yuan,3.31 times the average output 2 613 yuan of the Jiuzhaigou citizens ecological footprint.(4) Takes the direct lost benefits of De-farming and Reafforestation as the lowest eco-compensation level,Jiuzhaigou residents should be paid 2 159 yuan per family or 472 yuan per person.Takes the adding recreational benefits of De-farming and Reafforestation as the highest eco-compensation level,Jiuzhaigou residents should be paid 7 142 yuan per family or 1 561 yuan per person.Takes the difference of economic efficiency of ecological footprint between tourists and residents as a reasonable level,Jiuzhaigou residents should be paid 4 983 yuan per family or 1 088 yuan per person.
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    Analysis on the Fluctuation of Grain Output in China and Its Causes at Multi-time Scale Based on Empirical Mode Decomposition Method
    LIU Hui-yu, LIN Zhen-shan, ZHANG Ming-yang
    2005, 20 (5):  745-751.  doi: 10.11849/zrzyxb.2005.05.014
    Abstract ( )   PDF (238KB) ( )   Save
    Grain security is a very important issue which has a significant influence on the social stability of both a country and a region.Meanwhile,the fluctuation of grain output has a close relation with grain security.Thereby,the researches on the periods,amplitudes and characteristics of the fluctuation of grain output and its causes are propitious to reduce the intensity of the fluctuation,to eliminate unfavorable factors,and further to keep the stability of grain output to insure grain security.Empirical Mode Decomposition(EMD) is a powerful method for analyzing the nonlinear and non-stationary time series.Different from the traditional method in doing integral transformation to signal,it decomposes signal into several intrinsic mode functions (IMFs),which contain and extrude the local characters of signal.So the characteristic information of the original signal can be well held by analyzing the IMFs.Therefore,EMD method was introduced to study the fluctuation of grain production in China and its causes at multi-time scale,and the data have been decomposed into two IMFS and a residual trend term.The conclusions are drawn :1)The fluctuations of grain output have 3-year and 9-year time scales.Hereinto,fluctuation of the 9-year time scale is more prominent.Shown from the residual trend term,the grain output has increased continually since 1949,but stagnated after 1996. 2)We have decomposed the data of per capita grain yield and cultivated land by EMD.We found that per capita grain yield is the control factor of the 3-year fluctuation of grain output while cultivated land is the main influencing factor of the 9-year fluctuation of grain yield,moreover,the national policy and natural disasters also influence the 9-year fluctuation of grain yield to a certain degree.Therefore,in order to eliminate the short-term unfavorable factors,we must improve the foundation of grain production,add the investment in science and technology and enhance the ability of disaster prevention so as to stabilize per capita grain yield.With regarded the elimination of the long-term unfavorable factors,we should control the decrease in cultivated land.3)Analysis on the periodic fluctuation of the two time scales revealed that the grain output will decrease in the recent 2~3 years,but it will soon reverse to increase for a long time.Meanwhile,the amplitudes of the oscillation of grain output is increasing,which indicates that it is possible for the grain output to increase or decrease with big amplitudes.So it is urgent to take measures to guarantee the grain security in the case of crop failure.
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    An Integrated Assessment Method of Water Quality & Quantity Applied to Evaluation of Available Water Resources
    XIA Jun, WANG Miao-lin, WANG Zhong-gen, NIU Cun-wen, YAN Dong
    2005, 20 (5):  752-760.  doi: 10.11849/zrzyxb.2005.05.015
    Abstract ( )   PDF (271KB) ( )   Save
    Affected by human activity and climate change,substantial changes have taken place in both external environment and internal conditions in China's water resources.In the context of assessment,planning and management of sustainable utilization of water resources,the urgent need is to clarify how much available and regulatory water resources does a river have,under certain "production and domestic water consumptions" conditions,to satlisfy water quality objective for water functional regionalization and a certain river channel eco-water requirement so as to meet the demand of reducing pollution load for realizing water functional regionalization objective.To this end,this paper addresses the concept of the availabe useable water resources related to both water quality and quantity.An integrated assessment model and method of water quality and quantity,applied to single river section and multiple sections in a river system and basin,are developed.The case study of Luanhe river basin in North China is given as a preliminary explanation of this methodology.It is shown that under the present water use situation,new water use can lead to an increase of 510 million m3 when water quality objective of the river system is satisfied,where the maximum water availability is 43% and the present rate of the Luanhe River is only 30%.However,if the present water use pattern is replaced by reasonable water allocation,the maximum capacity of the available water can be increased to 54%.
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    Forests and Streamflow-Consistence and Complexity
    WEI Xiao-hua, LI Wen-hua, ZHOU Guo-yi, LIU Shi-rong, SUN Ge
    2005, 20 (5):  761-770.  doi: 10.11849/zrzyxb.2005.05.016
    Abstract ( )   PDF (105KB) ( )   Save
    Evaluation of the relationship between forest changes and streamflow has an important role in forest planning and water resource management.Although numerous studies on the subject have been conducted in various countries over the last century,controversies still exist.This is mainly due to the complexities of the relationship and the variations between the studied forest ecosystems.This paper examines both consistence and complexity of the forest-streamflow relations by reviewing the topics including the impacts of forest changes on streamflow,harvesting thresholds and hydrological recovery.The literatures used for this review are all from the paired watershed experiments.Our review shows that a consistent or predictable relationship generally exists when examining annual mean flow.The majority of the paired watershed studies demon-strated that harvesting increases annual mean flow,and reforestation from open land decreases it. The relationship between forest change and the short-duration hydrological variables such as peak and low flows appears more complex and less predictable.This is because many factors including changes in forest vegetation,soil condition,harvesting location,etc.interactively affect peak and low flows.Application of various definitions and analytical methods in streamflow also contributes to the complexities.We further conclude that a systematic approach considering interactions between streamflow and other processes or components(e.g.forest vegetation,soil and climate)is needed for understanding the forest-streamflow relation.The paired watershed approach is generally thought as a reliable method.However,it may offer limited use in evaluating complexity of the forest-streamflow relation if the paired watersheds are treated as the"black boxes".We suggest that combination of the paired watersheds with other process-related approaches should be used for studying the relationship between forest changes and streamflow in the future.
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    The Impact Assessment of Ecotourism in Nature Reserves: Progress and Implications
    LIU Yang, LU Yi-he, CHEN Li-ding, CHEN Fei-xing
    2005, 20 (5):  771-779.  doi: 10.11849/zrzyxb.2005.05.017
    Abstract ( )   PDF (262KB) ( )   Save
    The effective management of nature reserves has increasingly become the focus of atten-tion among researchers and governmental and nongovernmental organizations.The development and management of ecotourism thus also become a crucial issue in the management process of nature reserves and need to be treated seriously.Therefore,it is of great significance to the study of the impacts of ecotourism in nature reserves,and based upon which,to the establishment of criteria or an assessment index system for ecotourism in nature reserves for the theoretic advancement and scientification of practice of nature reserve management.This paper reviewed the methods and main progress of environmental and socioeconomic impact assessment researches on ecotourism in nature reserves,and noted that there was a considerable gap between actual effects and theoretical expectations of ecotourism,hence resulting in many practical problems.These can be treated as good warning signs for the management of nature reserves in China.Under the situation of the rapid increase in the number of nature reserves and great passion of ecotourism development in China,three tasks should be emphasized:1)to enhance the research on ecotourism in nature reserves;2)to strengthen planning,management and monitoring of ecotourism in nature reserves;and 3)to enlarge the economic contributions of ecotourism development in nature reserves.
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    Technical Approach to Resources Utilization of Rainfall Runoff in Rivers of Dianchi Lake Watershed
    LIU Zhong-han, WANG Hai-ling, PENG Jiang-yan, DENG De-ren
    2005, 20 (5):  780-789.  doi: 10.11849/zrzyxb.2005.05.018
    Abstract ( )   PDF (321KB) ( )   Save
    Based on the results of land treatment demonstration project which were conducted in Kunming and Chuxiong cities of Yunan province at various periods,the removal rates of BOD5, CODCr,TP,KN,NH3-N and suspended solid (SS) by using Slow Rate land treatment (SR) system for municipal wastewater was 84.3%,82.5%,94.9%,85.8%,89.4% and 58.4%,respectively.The core skills for ensuring steady operation of this ecological project all the year round are the stabilities of effluent quality and quantity.The main factors relating to stabilities of both include water regulation system in seasons when no water required for crop growth (harvesting and seeding),the treatment techniques relating to rainy season steady operation in and high removal rates,environmental factors such as weather and soil conditions suitable for slow rate infiltration land treatment (SR) operation, and the effective guarantees of water balance regulation and management.The most important technical guarantees for resources utilization of rainfall runoff are the implementation of sectionalized interception management in catchment areas and hydraulic engineering which can improve regulation capability of underlying surface drainage in combination with the use of ecological techniques such as slow rate land treatment (SR) for crop irrigation type or wetland for vegetated submerged bed (VSB), etc. As pollutants from outside sources were not effectively controlled in Dianchi lake catchment water pollution control,the most important approach to control river pollution is to reduce water quantity of surface runoff entering river in rainy season and water quality improvement,to make use of treated wastewater of rain water and rainfall runoff as a resource,and to make the renovated clean water enter into planned specific rivers or drainage channels to supplement eco-water use of Dianchi Lake.
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    Remediation of Subsided Land and Creation of Constructed Wetland in Mining Area-A case of Remediation of Subsided Land in Xuzhou Mining Area
    LIN Zhen-shan, WANG Guo-xiang
    2005, 20 (5):  790-795.  doi: 10.11849/zrzyxb.2005.05.019
    Abstract ( )   PDF (207KB) ( )   Save
    There is a subsided area covering 4 700~5 300 ha sunk as perennial or seasonal pond-ings in Xuzhou mining area.The average depth of water in these pondings is about 3~3.5m and the deepest ponding is about 7m.It is impossible to recultivate this kind of subsided area.For making use of the deeply subsided area,several types of constructed wetlands are proposed to build.On the basis of the characteristics of natural environment,hydrology,river system,sunk degree of the subsided area,three types of constructed wetlands including decontaminated constructed wetland,fishery constructed wetland and landscape constructed wetland can be built.The decontaminated constructed wetland should be built in shallow pondings,especially in some seasonal pondings or perennial poundings with a water depth no more than 0.5m.The aquatic and wetland plants,such as reed and cattail,can be introduced to the decontaminated constructed wetlands.The principles of choosing wetland plants are that these plants should be native with strong purification capacity and economic efficiency.The reed wetland has both economic efficiency and strong purification capacity,hence the subsided area can be improved by creating constructed wetlands.Such a measure adopted should also be suitable to local conditions,especially for Xuzhou,as water is shoutage in the city.The remediation of constructed wetland can not only withhold precipitation resource but also reuse tail water of wastewater so as to mitigate the contradition of water shortage issue.
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